CF

My Codeforce Practice

奇怪的知识

1.笛卡尔树1
2.笛卡尔树2
3.线性基
4.线性基
5.三分
6.树点分治
7.中国余数 1
7.中国余数 2
8.中国余数 3
9.中国余数 Code
10.欧拉函数

Archive

https://github.com/JunBinLiang/Leetcode-Complete-Guide

每日刷题挑战

#	Title	Date
1485A	Add and Divide (1000)	2021/02/15
1485B	Replace and Keep Sorted (1200)	2021/02/15
1485C	Floor and Mod (1700) (Math+Binary Search)	2021/02/15
1485D	Multiples and Power Differences (2200)	2021/02/15
1485F	Copy or Prefix Sum (2400) Venice Technique	2021/02/16
1467B	Hills And Valleys (1700) (Brute force)	2021/02/17
845C	Luba And The Ticket (1600) (Brute force)	2021/02/17
272D	Dima and Two Sequence (1600) (Combination)	2021/02/17
1490G	Old Floppy Drive (1900) (Prefix + Binary Search)	2021/02/17
1329B	Dreamoon Likes Sequences (1700) (Bitmask)	2021/02/17
1478C	Nezzar and Symmetric Array (1700) (Math + Sort)	2021/02/18
1478B	Nezzar and Lucky Number (1100)	2021/02/18
1479B1	Painting the Array I (1900) (Greedy)	2021/02/18
776D	The Door Problem (2000) (2 Sat)	2021/02/18
1475F	Unusual Matrix (1900) (2 Sat)	2021/02/18
1475G	Strange Beauty (1900) (Dp+打表)	2021/02/18
1475E	Advertising Agency (1600) (Combination + Sort)	2021/02/18
1475C	Ball in Berland (1400) (Math)	2021/02/18
621E	Wet Shark and Blocks (2000) (Matrix Exponent + DP)	2021/02/19
1469B	Red and Blue (1000) (Prefix)	2021/02/19
608C	Chain Reaction (1600) (DP)	2021/02/19
1475D	Cleaning the Phone (1800) (Binary Search + Sort)	2021/02/19
1475B	New Year's Number (900) (Math)	2021/02/19
1472D	Even-Odd Game (1200) (Game)	2021/02/19
1400B	RPG Protagonist (1700) (Math + Greedy)	2021/02/19
1400C	Binary String Reconstruction (1500) (Implementation)	2021/02/19
1400D	ZigZag (1900) (Math + DP)	2021/02/19
1476C	Longest Simple Cycle (1600) (Observation + Graph + Greedy)	2021/02/20
1487C	Minimum Tile (1500) (Math)	2021/02/22
1487D	Pythagorean Triples (1500) (Math + BinarySearch)	2021/02/22
1487E	Cheap Dinner (2000) (Greedy + Sort)	2021/02/22
1470B	Strange Definition (1900) (Math + Hash + Bit)	2021/02/24
1472F	New Year's Puzzle (2100) (DP)	2021/02/24
1472E	Correct Placement (1700) (Sort + Two pointer)	2021/02/24
1468J	Road Reform (1800) (UF + Greedy)	2021/02/25
1468A	LaIS (2200) (DP+Greedy+Segment Tree)	2021/02/25
1468K	The Robot (1600) (Brute force)	2021/02/25
1468D	Firecrackers (1700) (Binary Search)	2021/02/25
1468H	K and Medians (2200) (Greedy + Reverse Thinking)	2021/02/25
1492D	Genius's Gambit (1900) (Greedy + Observation)	2021/02/26
1492C	Maximum width (1500) (DP + Binary Search)	2021/02/26
1486D	Max Median (2100) (Binary Search)	2021/02/26
1468C	Berpizza (1400) (Implementation)	2021/02/26
1364C	Ehab and Prefix MEXs (1600) (Greedy + BIT)	2021/02/27
1389C	Good String (1500) (Obsercation + Brute Force)	2021/02/27
1481C	Fence Painting (1600) ( Brute Force)	2021/02/27
1472G	Moving to the Capital (2100) ( Graph + DP)	2021/02/28
1474C	Array Destruction (1700) ( Brute force + Greedy)	2021/02/28
1363C	Game On Tree (1600) ( Game + Greedy)	2021/03/01
1491C	Pekora and Trampoline (1700) ( Greedy)	2021/03/01
1491B	Minimal Cost (1200) (Brute Force)	2021/03/01
1491D	Zookeeper and The Infinite Zoo (1800) (Bit)	2021/03/01
1486B	Eastern Exhibition (1500) (Geometry)	2021/03/01
1491E	Fib-tree (2400) (Tree + Greedy + Brute Force)	2021/03/02
1156C	Match Points (2000) (Binary Search)	2021/03/02
1156D	0-1-Tree (2200) (UF + Math)	2021/03/03
1156B	Ugly Pair (1800) (Greedy)	2021/03/03
1156A	Inscribed Figures (1400) (Geometry)	2021/03/03
1156E	Special Segments of Permutation (2200) (Divide Conquer + Segment Tree)	2021/03/03
740C	Alyona and mex (1700) (Greedy)	2021/03/03
740D	Alyona and a tree (1900) (Tree + Binary Search + BIT + Prefix)	2021/03/04
1353D	Constructing the Array (1600) （Sort + Implementation）	2021/03/04
1353E	K-periodic Garland (1900) （DP + Sliding Window）	2021/03/04
33C	Wonderful Randomized Sum (1800) （DP + Greedy）	2021/03/05
1353F	Decreasing Heights (2200) （DP + Brute Force）	2021/03/05
1451D	Circle Game (1700) （Game）	2021/03/06
1494C	1D Sokoban (1900) （Binary Search + Greedy + Math）	2021/03/10
1494A	ABC String (900) （Bit）	2021/03/11
1495B	Let's Go Hiking (1900) （Game）	2021/03/11
1495A	Diamond Miner (1200) （Greedy + Sort）	2021/03/11
1492E	Almost Fault-Tolerant Database (2500) （Backtracking + Time complexity）	2021/03/12
1500A	Going Home (1800) （Brute Force）	2021/03/14
687B	Remainders Game (1800) （Number Theory）	2021/03/14
1493C	K-beautiful Strings (2000) （Greedy + Constructive）	2021/03/15
1393C	Pinkie Pie Eats Patty-cakes (1700) （Greedy + Constructive）	2021/03/15
1493D	GCD of an Array (2100) （Brute Force + Number Theory）	2021/03/16
1102E	Monotonic Renumeration (1700) （Combination）	2021/03/17
1497C2	k-LCM (hard version) (1600) （Greedy）	2021/03/17
1102D	Balanced Ternary String (1500) （Greedy）	2021/03/17
1497E1	Square-free division (easy version)(1700) （Greedy）	2021/03/18
1497E2	Square-free division (hard version)(2500) （Dp + Sliding Window + Hash）	2021/03/19
1102B	Array K-Coloring (1400) （Greedy）	2021/03/19
1102F	Elongated Matrix (2000) （Dp + Bitmask）	2021/03/19
180D	Name (1900) （Greedy + String）	2021/03/19
180E	Cubes (1800) （Slding window + Segment Tree）	2021/03/19
1499C	Minimum Grid Path (1500) （Math）	2021/03/21
1499D	The Number of Pairs (2100) （Math）	2021/03/21
1481D	AB Graph (2000) （Graph + Greedy + Constructive）	2021/03/22
1481E	Sorting Book (2500) （DP + 观察 + 思维）	2021/03/23
1140C	Playlist (1600) （Sort）	2021/03/24
1140F	Extending Set of Points (2600) （Dynamic Connectivity）	2021/03/24
981E	Addition on Segments (2200) （Dp + Segment Tree + Divide Conquer）	2021/03/24
1466E	Apollo versus Pan (1800) （Bit + Math）	2021/03/24
1270C	Make Good (1400) （Constructive）	2021/03/25
1282B2	K for the Price of One (Hard Version) (1600) （Greedy）	2021/03/25
1278D	Segment Tree (2100) （Sort + TreeMap + UF）	2021/03/25
1282C	Petya and Exam (1800) （Sort + Math）	2021/03/25
1328F	Make k Equal (2200) （Sort + Math + Brute Force）	2021/03/25
1328D	Carousel (1800) （Constructive + Greedy）	2021/03/26
1328E	Tree Queries (1900) （LCA + Sprase Table + Thinking）Thumb up!	2021/03/26
1506D	Restoring the Permutation (1500) （Greedy + Constructive）	2021/03/27
1506G	Maximize the Remaining String (2000) （Greedy + Stack）	2021/03/27
1506F	Triangular Paths (2000) （Math）	2021/03/27
1227D2	Optimal Subsequences (Easy Version) (1800) （Greedy + Fenwick + BinarySearch）	2021/03/28
1227C	Messy (1700) （Constructive）	2021/03/28
1499E	Chaotic Merge (2400) （DP + Combination）	2021/03/29
1381A2	Prefix Flip (Hard Version) (1700) （Constructive + Two Pointer）	2021/03/29
1388C	Uncle Bogdan and Country Happiness (1800) （Tree + Math）	2021/03/30
1343D	Constant Palindrome Sum (1700) （Line Sweep）	2021/03/30
1269B	Modulo Equality (1500) （Brute Force）	2021/03/30
1269C	Long Beautiful Integer (1700) （Greedy）	2021/03/30
297A	Parity Game (1700) （智力题）	2021/03/30
1343E	Weights Distributing (2100) （Greedy + Graph）	2021/03/31
1251D	Salary Changing (1900) （Binary Search）	2021/04/01
1496B	Max and Mex (1100) （Math + Greedy）	2021/04/01
1486E	Paired Payment (2200) （Graph + SPFA）	2021/04/01
1379C	Choosing flowers (2000) （Binary Search + Math）	2021/04/02
1348C	Phoenix and Distribution (1600) （Greedy + Constructive）	2021/04/02
888D	Almost Identity Permutations (1600) （Combination ）	2021/04/02
888E	Maximum Subsequence (1800) （Divide Conquer + Meet in Middle ）	2021/04/02
1335E2	Three Blocks Palindrome (hard version) (1800) （Two Pointer + Prefix sum ）	2021/04/02
1503A	Balance the Bits (1600) （Constructive ）	2021/04/02
1503C	Travelling Salesman Problem (2200) （Constructive +Greedy ）	2021/04/06
1253D	Harmonious Graph (1700) （Graph + UF）	2021/04/07
1253C	Sweets Eating (1500) （Math + DP）	2021/04/07
1223D	Sequence Sorting (2000) （DP）	2021/04/07
1467C	Three Bags (1900) （Greedy）	2021/04/07
1093D	Beautiful Graph (1700) （Bipartile Graph + Math）	2021/04/08
174C	Range Increments(1800) （差分 + Constructive）	2021/04/08
1141F2	Same Sum Blocks (Hard) (1900) （DP）	2021/04/08
1141C	Polycarp Restores Permutation (1500) （Math + Constructive）	2021/04/08
1141D	Colored Boots (1500) （Greedy）	2021/04/08
1141E	Superhero Battle (1700) （Math）	2021/04/09
1141G	Privatization of Roads in Treeland (1900) （Greedy + Graph + Tree）	2021/04/09
1338B	Edge Weight Assignment (1800) （Greedy + Bit + Tree）	2021/04/09
1338A	Powered Addition (1500) （Greedy）	2021/04/09
1223E	Tree Painting (2100) （Tree + DP + Sort）	2021/04/09
1110D	Jongmah (2200) （DP + Greedy）	2021/04/10
1415D	XOR-gun (2000) （Brute Force + Greedy）	2021/04/10
910B	Door Frames (1600) （ DFS ）	2021/04/11
910C	Minimum Sum (1700) （Greedy）	2021/04/11
1411C	Peaceful Rooks (1700) （Cycle Direct Graph）	2021/04/12
1411D	Grime Zoo (2100) （Greedy + Brute Force）	2021/04/12
940E	Cashback (2000) （Greedy + DP + MonoQueue）	2021/04/13
940C	Phone Numbers (1500) （Greedy + Constructive）	2021/04/13
252B	Unsorting Array (1800) （Brute Force + Time Complexity）	2021/04/13
652C	Foe Pair (1800) （Two Pointer + Sort + Binay Search）	2021/04/14
652D	Nested Segments (1800) （Sort + Divide Conquer）	2021/04/14
919D	Substring (1700) （DP + Topological Sort + Direct Graph Cycle Detection）	2021/04/14
1511D	Min Cost String (1600) （Constructive）	2021/04/14
86D	Powerful Array (2200) （莫队）	2021/04/14
940F	Machine Learning (2600) （莫队修改）	2021/04/15
1207D	Number Of Permutations (1800) （Combination + 容斥）	2021/04/15
1512E	Permutation by Sum(1600) （Brute Force + Constructiv + Induction）	2021/04/15
1512G	Short Task (1700) （Brute Force + 打表）	2021/04/15
1512F	Education (1900) （Math + DP）	2021/04/15
1513B	AND Sequences (1400) （Bit + Greedy + Combination）	2021/04/16
1513C	Add One (1600) （DP）	2021/04/16
1513D	GCD and MST (2000) （Sort + Greedy + Graph）	2021/04/16
1333C	Eugene and an array (1700) （Prefix + Two pointer）	2021/04/16
1513E	Cost Equilibrium (2300) （Observation + Combination）	2021/04/16
237E	Build String (2000) （Minimum Cost Max Flow ）	2021/04/16
1325D	Ehab the Xorcist (1700) （Bit + Greedy ）	2021/04/17
1511E	Colorings and Dominoes (2100) （DP + Combination ）	2021/04/19
584D	Dima and Lisa (1800) （Math : 1个偶数可以拆两个素数 ）	2021/04/19
485D	Maximum Value (1900) （Time Complexity + Sort + BinarySearch ）	2021/04/19
416D	Population Size (2400) （Greedy + Heavy Implementation）	2021/04/19
416E	President's Path(2500) （Shortest Path + DP）	2021/04/19
577B	Modulo Sum (1900) （鸽子原理 + DP）(对prefixsum 进行鸽子原理)	2021/04/20
577C	Vasya and Petya's Game (1500) (Number Theory + Observation)	2021/04/20
1234D	Distinct Characters Queriese (1600) (TreeSet)	2021/04/20
176B	Word Cut (1700) (DP + Observation)	2021/04/20
1234E	Special Permutations (2000) (Math)	2021/04/20
1234F	Yet Another Substring Reverse (2200) (DP + Bit subset dp)	2021/04/21
1234C	Pipes (1500) (Implementation)	2021/04/21
1256E	Yet Another Division Into Teams (2000) (DP + Greedy)	2021/04/21
1256F	Equalizing Two Strings (2000) (Sort + Greedy + Thinking)	2021/04/21
1203D2	Remove the Substring (hard version) (1700) (Binary Search)	2021/04/21
1177B	Digits Sequence (Hard Edition) (1800) (Binary Search + Math)	2021/04/21
1157C2	Increasing Subsequence (hard version) (1500) (Greedy)	2021/04/21
1157D	N Problems During K Dayse (hard version) (1900) (Constructive (Induction) + Greedy + Binary Search )	2021/04/21
1157F	Maximum Balanced Circle (2000) (Greedy + Constructive )	2021/04/22
1157G	Inverse of Rows and Columns (2200) (Brute Force + 2-sat )	2021/04/22
1516C	Baby Ehab Partitions Again (1700) (Math + Greedy )	2021/04/22
1516D	Cut (2100) (Sparse Table + Sliding Window + Prime )	2021/04/22
1514D	Cut and Stick (2000) (Greedy + 莫队 + Update max)	2021/04/22
1509C	The Sports Festival (1800) (DP)	2021/04/23
1508A	Binary Literature (1900) (Greedy) (Thumb)	2021/04/24
977E	Cyclic Components (1500) (Graph)	2021/04/24
977F	Consecutive Subsequence (1700) (DP)	2021/04/24
977D	Divide by three, multiply by two (1400) (Sort + Greedy)	2021/04/24
1175E	Minimal Segment Cover (2200) (Sparse Table + Interval)	2021/04/25
1203F1	Complete the Projects (easy version) (2100) (Greedy + Sort) (Thump)	2021/04/25
126B	Password (1700) (KMP+ Z algorithm)	2021/04/25
1144G	Two Merged Sequences (2400) (Greedy) (Thumb)	2021/04/26
1196D2	RGB Substring (hard version)(1600) (DP)	2021/04/26
987E	Petr and Permutations (1800) (思维 + 逆数对)	2021/04/26
1473D	Program (1700) (DP + Prefix)	2021/04/26
1196E	Connected Component on a Chessboard (1800) (Chessboard + Constructive + Greedy)	2021/04/26
1516E	Baby Ehab Plays with Permutations (2500) (超难 Combination + DP + 容斥 + Permutation)	2021/04/28
1334C	Circle of Monsters (1600) (思维 + Brute Force)	2021/04/28
1334D	Minimum Euler Cycle (1800) (Graph + Greedy + Constructive + Math)	2021/04/28
1196F	K-th Path (2200) (思维 + Shortest Path + Floy + Brute Force)	2021/04/28
1278C	Berry Jam (1700) (DP + Left Right)	2021/04/29
1208D	Restore Permutation (1900) (Constructive + Thinking + Fenwick Tree)	2021/04/29
1208C	Magic Grid (1800) (Constructive)	2021/04/29
1167E	Range Deleting (2100) (Two Pointer + DP)	2021/04/30
102D	Buses (1700) (Binary Search + DP + Prefix)	2021/04/30
1133E	K Balanced Teams (1800) (DP)	2021/05/01
1133F1	Spanning Tree with Maximum Degree (1600) (Greedy + Graph)	2021/05/01
1133F2	Spanning Tree with One Fixed Degree (1900) (Greedy + Graph + UF + Strongly Connect)	2021/05/01
1519D	Maximum Sum of Products (1600) (Observation)	2021/05/02
1515E	Phoenix and Computers (2200) (DP + Combination)	2021/05/03
1108E1	Array and Segments (Easy version) (1800) (Brute Force)	2021/05/03
1108E2	Array and Segments (Hard version) (2100) (差分 + DP + Prefix)	2021/05/03
1355C	Count Triangles (1800) (Binary Search + Sliding Window)	2021/05/04
1301C	Ayoub's function (1700) (Math + Greedy)	2021/05/04
1185C2	Exam in BerSU (hard version) (1700) (Math )	2021/05/05
1185D	Extra Element (1700) (Prefix DP )	2021/05/05
1185E	Polycarp and Snakes (2000) (Brute Force + Implementation )	2021/05/05
1185F	Two Pizzas (2100) (Brute Force + Bit )	2021/05/05
1185G1	Playlist for Polycarp (easy version) (2100) (Bitmask DP )	2021/05/05
1174D	Ehab and the Expected XOR Problem (1900) (bit + Thinking + Prefix )	2021/05/05
1185G2	Playlist for Polycarp (Hard version) (2600) (DP + Combination )	2021/05/06
161D	Distance in Tree (1800) (Tree DP )	2021/05/06
926J	Segments (2100) (Tree Set + Merge Set )	2021/05/07
540E	Infinite Inversions (2100) (无限逆序对+ Fenwick Tree + Thinking )	2021/05/07
540B	School Marks (1700) (Greedy )	2021/05/07
1520G	To Go Or Not To Go? (2200) (Graph + Shortest Path )	2021/05/08
1217C	The Number Of Good Substrings (1700) (Brute Force )	2021/05/08
540D	Bad Luck Island (1900) (DP)	2021/05/08
1359D	Yet Another Yet Another Task (2000) (Brute Force)	2021/05/09
1359E	Modular Stability (2000) (Thinking + Number Theory + Combination)	2021/05/09
1520F1	Guess the K-th Zero (Easy version) (1600) (Binary Search)	2021/05/10
1520F2	Guess the K-th Zero (Hard version) (2200) (Binary Search+ Divide Conquer)	2021/05/10
1354D	Multiset (1900) (Fenwick Tree)	2021/05/10
1354E	Graph Coloring (2100) (DP + Bipartite Graph)	2021/05/11
1473E	Minimum Path (2400) (Shortest Path)	2021/05/11
1295D	game GCDs (1800) (GCD + Euler)	2021/05/11
448D	Multiplication Table (1800) (Binary Search)	2021/05/11
448E	Divisor (2200) (DFS + 剪枝)	2021/05/12
313D	Ilya and Roads (2100) (DP)	2021/05/13
313E	Ilya and Two Numbers (2300) (Greedy + Thinking + Sort)	2021/05/13
66D	Petya and His Friends (1700) (Constructive)	2021/05/14
66E	Petya and Post(2000) (DP + Thinking)	2021/05/14
125C	Hobbits' Party (1600) (Constructive)	2021/05/17
125E	MST Company (2400) (MST + Thinking)	2021/05/17
276D	Little Girl and Maximum XOR (1700) (Bit + Greedy)	2021/05/17
125D	Two progressions (2200) (Greedy + 鸽子)	2021/05/18
57C	Array (1900) (Combination) (Thumb)	2021/05/18
962D	Merge Equals (1600) (Implementation)	2021/05/19
21C	Stripe 2 (2000) (Dp)	2021/05/19
37C	Old Berland Language (1900) (Dfs + Trie)	2021/05/19
37E	Trial for Chief(2600) (Shortest Path + Thinking) (Thumb)	2021/05/20
1205B	Shortest Cycle(1900) (Shortest Cycle in Weight1) (Thumb)	2021/05/20
1525D	Armchairs (1800) (DP)	2021/05/21
123D	String (2300) (Suffix Array LCP + Stack)	2021/05/22
78C	Beaver Game (2000) (Game)	2021/05/23
190D	Non-Secret Cypher (1900) (Two Pointer + Segment Tree)	2021/05/23
45J	Planting Trees (1800) (Constructive)	2021/05/23
45D	Event Dates (1900) (Sort)	2021/05/23
45C	Dancing Lessons (1900) (TreeMap)	2021/05/23
45G	Prime Problem (2200) (Number Theory + Constructive)	2021/05/23
45E	Director (2000) (Greedy + Implementation)	2021/05/24
45B	School (2200) (DP + Sparse Table + Brute Force + Time)	2021/05/25
52C	Circular RMQ (2200) (Range Update Min Lazy Seg)	2021/05/25
52B	Right Triangles (1600) (Combination)	2021/05/26
31D	Chocolate (2000) (Brute Force + Implementation + Geometry)	2021/05/26
31E	TV Game (2400) (DP)	2021/05/26
5E	Bindian Signalizing (2400) (Stack + Thinking + Observation)	2021/05/27
1528A	Parsa's Humongous Tree (1600) (Tree + DP)	2021/05/28
1529D	Kavi on Pairing Duty (1700) (Thinking + DP)	2021/05/29
1527B1	Palindrome Game (easy version) (1200) (Game)	2021/05/30
1527B2	Palindrome Game (hard version) (1900) (Game)	2021/05/30
1527C	Sequence Pair Weight (1600) (DP)	2021/05/30
39E	What Has Dirichlet Got to Do with That?(2000) (DP + Game + Optimization + MinMax)	2021/05/30
1474D	Cleaning (2200) (Thinking + Left/Right DP)	2021/05/30
33B	String Problem (1800) (Shortest Path + Direct Graph)	2021/05/30
224B	Array (1500) (Two Pointer + Thinking)	2021/05/31
224C	Bracket Sequence (1700) (Stack)	2021/05/31
224D	Two Strings (1900) (left-right DP +Binary Search)	2021/05/31
224E	Partial Sums (1900) (Combination)	2021/05/31
279D	The Minimum Number of Variables(2200) (Bit DP)	2021/05/31
279E	Beautiful Decomposition(1900) (Bit + DP)	2021/06/01
279C	Ladder (1700) (Segment Tree +Left-right DP)	2021/06/02
46E	Comb (1900) ( DP)	2021/06/02
1294E	Obtain a Permutation (1900) (Implementation)	2021/06/02
888G	Xor-MST (2300) (MST + Trie + Bit + Divide Conquer + Boruvka's algorithm)	2021/06/02
988D	Points and Powers of Two (1800) (Observation + Thinking + Brute Force)	2021/06/02
988E	Divisibility by 25 (2100) ( Brute Force)	2021/06/03
988F	Rain and Umbrellas (2100) ( DP)	2021/06/03
32C	Flea (1700) ( Math )	2021/06/04
1183H	Subsequences (hard version) (2000) ( DP + Distinct Subsequence )	2021/06/04
1183G	Candy Box (hard version) (hard version) (2000) ( Sort + Greedy )	2021/06/04
1183F	Topforces Strikes Back (hard version) (2100) ( Brute Force + Time + Math )	2021/06/05
15C	Industrial Nim (2000) ( Nim Game + Bit )	2021/06/05
27D	Ring Road 2(2200) ( Bipartile Graph)	2021/06/06
22C	System Administrator (1700) ( Constructive + Graph)	2021/06/06
1536C	Diluc and Kaeya (1500) ( DP + HashMap)	2021/06/06
1536D	Omkar and Medians (2000) ( Thinking + Observation)	2021/06/07
1536E	Omkar and Forest (2300) (Combination + Multiple BFS)	2021/06/07
24A	Ring Road (1400) (Graph)	2021/06/07
479E	Riding in a Lift (1900) (DP + Prefix Sum)	2021/06/08
450B	Jzzhu and Sequences (1300) (Matrix)	2021/06/08
450D	Jzzhu and Cities (2000) (Shortest Path + Thinking) (Thumb)	2021/06/09
450E	Jzzhu and Apples (2500) (Greedy)	2021/06/09
978G	Petya's Exams (1700) (Greedy + Sort)	2021/06/09
222E	Decoding Genome (1900) (DP + Matrix)	2021/06/10
222A	Shooshuns and Sequence (1200) (Observation + Thinking)	2021/06/10
222C	Reducing Fractions (1800) (超级打表) （Thump）	2021/06/10
1015D	Walking Between Houses (1600) (Constructive)	2021/06/10
1015F	Bracket Substring (2300) (DP + KMP)	2021/06/10
1015E2	Stars Drawing (Hard Edition) (1900) (DP)	2021/06/11
27E	Number With The Given Amount Of Divisors (2000) (DFS)	2021/06/12
316C1	Tidying Up (2200) (Maximum Flow Minimum Cost)	2021/06/13
1029D	Concatenated Multiples (1900) (Hash + Mod)	2021/06/13
1029E	Tree with Small Distances (2100) (Tree DP)	2021/06/14
1029F	Multicolored Markers (2000) (Two Pointer)	2021/06/14
1029C	Maximal Intersection (1600) (Left/Right DP + Interval Problem)	2021/06/15
1029A	Many Equal Substrings (1300) (KMP)	2021/06/15
1439B	Graph Subset Problems (2600) (Graph)	2021/06/16
341D	Iahub and Xors(2500) (二维差分+2D Fenwick)	2021/06/16
1439C	Greedy Shopping (2600) (Segment Tree Range Update + Segment Tree Binay Search)	2021/06/16
58C	Trees (1800) (Implentation)	2021/06/17
61D	Eternal Victory (1800) (Tree)	2021/06/17
1066E	Binary Numbers AND Sum (1700) (Prefix)	2021/06/18
1066D	Boxes Packing (1800) (Binary Search)	2021/06/18
1066F	Yet another 2D Walking (2100) (DP + Math)	2021/06/18
1538G	Gift Set (2100) (BinarySearch + Math)	2021/06/19
1260E	Tournament (2400) (Greedy + Heap)	2021/06/19
89C	Chip Play (2300) (DFS + 十字linkedlist)	2021/06/20
213B	Numbers (1900) (DP + Combination)	2021/06/20
55C	Pie or die (1900) (Game)	2021/06/20
73B	Need For Brake (2000) (Greedy + Sort)	2021/06/21
1537D	Deleting Divisors (1700) (Game + Number Theory)	2021/06/21
1537E2	Erase and Extend (Hard Version) (2200) (Suffix Structure + Z-algorithm)	2021/06/22
1537F	Figure Fixing (2200) (Graph + Bipartile)	2021/06/22
1077F2	Pictures with Kittens (hard version) (2100) (DP + Monoqueue)	2021/06/23
1487F	Ones (2900) (DP + Observation)	2021/06/23
1092F	Tree with Maximum Cost (1900) (Tree DP)	2021/06/23
1092E	Minimal Diameter Forest (2000)(Tree + Greedy)	2021/06/23
954I	Yet Another String Matching Problem (2200) (FFT)	2021/06/25
1092C	Prefixes and Suffixes (1700) (Brute Force)	2021/06/25
1095F	Make It Connected (1900) (MST + Greedy)	2021/06/26
1095C	Powers Of Two (1400) (Induction)	2021/06/26
1095D	Circular Dance (1600) (Implementation)	2021/06/26
1095E	Almost Regular Bracket Sequence (1900) (Implementation)	2021/06/26
1151E	Number of Components(2100) (Observation + Thinking + Contribution)	2021/06/28
1151B	Dima and a Bad XOR (1600) (Thinking + Observation)	2021/06/28
1151C	Problem for Nazar (1800) (Math)	2021/06/28
1151D	Stas and the Queue at the Buffet (1600) (Sort + Greedy)	2021/06/28
1151F	Sonya and Informatics (2300) (Matrix + DP + Probability) (Thunp)	2021/06/29
439D	Devu and his Brother (1700) (Binary Search + Convex Line)	2021/06/29
439C	Devu and Partitioning of the Array (1700) (Constructive)	2021/06/29
439E	Devu and Birthday Celebration (2100) (Combination)	2021/06/29
571B	Minimization (2000) (DP + k skip)	2021/06/30
571A	Lengthening Sticks (2100) (Combination + Ball in box)	2021/06/30
314C	Sereja and Subsequences (2100) (DP + Distince Subsequence + Fenwick Tree)	2021/06/30
466C	SNumber of Ways (1700) (DP + rihgt/prefix)	2021/06/30
466D	Increase Sequence (2100) (DP)	2021/06/31
466B	Wonder Room (2000) (Brute Force + Time Complexity)	2021/07/01
466E	Information Graph (2100) (OffLine + Sparse Table + Tree)	2021/07/2
558E	A Simple Task (2300) (Segment Tree Range Update)	2021/07/2
558C	Amr and Chemistry (1900) (Thinking + Time Complexity)	2021/07/2
484D	Kindergarten (2400) (DP + Greedy + Observation)	2021/07/3
1155D	Beautiful Array (1900) (DP + Kadane)	2021/07/4
484E	Sign on Fence (2500) (Persistant Segment Tree + Segment Tree Merge Interval + Binary Search)	2021/07/4
1242B	0-1 MST (1900) (MST + Graph)	2021/07/4
414A	Mashmokh and Numbers (1500) (GCD (a,a+1) == 1)	2021/07/4
903D	Almost Difference (2200) (Contribution)	2021/07/5
374B	Inna and Nine (1500) (Observation + Combination)	2021/07/5
1542C	Strange Function (1600) (Thinking + Math)	2021/07/5
1542B	Plus and Multiply (1500) (Thinking + Math)	2021/07/5
117C	Cycle (2000) (Graph)	2021/07/6
1285E	Delete a Segment (2300) (Interval Problem + TreeMap + BinarySearch + left/right DP + Segment Tree)	2021/07/6
1285C	Fadi and LCM (1400) (Math)	2021/07/6
1285D	Dr. Evil Underscores (1900) (Bit + Trie)	2021/07/6
626F	Group Projects (2400) (DP + Thinking)	2021/07/7
626D	Jerry's Protest (1800) (Combination + Probability)	2021/07/7
1188C	Array Beauty (2500) (DP + Brute Force + Time Complexity)	2021/07/8
1108F	MST Unification (2100) (MST + Thinking)	2021/07/8
895C	Square Subsets (2000) (DP + Combination + BitMask)	2021/07/9
1468M	Similar Sets (2300) (Graph + 四环图)	2021/07/10
911E	Stack Sorting (2000) (Constructive + Stack)	2021/07/10
911D	Inversion Counting (1800) (逆数对)	2021/07/11
744F	Tree Destruction (2400) (Tree + Greedy )	2021/07/11
1063B	Labyrinth (1800) (Thinking + 01-BFS )	2021/07/11
1025C	Plasticine zebra (1600) (Observation )	2021/07/12
1547G	How Many Paths? (2100) (Direct Graph Cycle + DP )	2021/07/12
1547F	Array Stabilization (GCD version) (1900) (Math + BinarySearch + Segment Tree + GCD )	2021/07/12
487B	Strip (2000) (DP + Monoqueue)	2021/07/12
1547E	Air Conditioners (1500) (left/right dp + sort)	2021/07/13
1400E	Clear the Multiset (2200) (Greedy + Divide Conquer)	2021/07/13
12E	Start of the session(2100) (Constructive)	2021/07/13
12D	Ball (2400) (Sort + Segment Tree)	2021/07/14
359D	Pair of Numbers (2000) (Binary Search + Sparse Table)	2021/07/14
359B	Permutations (1400) (Constructive)	2021/07/14
1217D	Coloring Edges (2100) (Direct - Graph + Thinking)	2021/07/14
360B	Levko and Array (2000) (DP)
1550D	Excellent Arrays (2300) (Combination) (Thumb)
1311E	Construct the Binary Tree (2200) (Constructive + Induction) (Thumb)
1443D	Extreme Subtraction (1800) (差分)
863E	Turn Off The TV (2000) (Interval Problem)
863D	Yet Another Array Queries Problem (1800) (Reverse + Thinking)	2021/07/16
1098B	Nice table (2100) (Constructive + Brute Force)	2021/07/16
404C	Restore Graph (1800) (Constructive + Graph)	2021/07/17
509C	Sums of Digits (2000) (Constructive + Greedy)	2021/07/17
292D	Connected Components (1900) (UF + Graph + Thinking)	2021/07/18
597C	Subsequences (1900) (DP + Fenwick)	2021/07/18
597B	Restaurant (1600) (DP + Binary Search)	2021/07/19
597A	Divisibility (1600) (Math)	2021/07/19
545E	Paths and Trees (2000) (shortest path + thinking)	2021/07/19
960F	Pathwalks (2100) (DP + Lazy Segment Tree)	2021/07/21
960D	Full Binary Tree Queries (2100) (Math + Tree)	2021/07/21
960C	Subsequence Counting (1700) (Constructive)	2021/07/21
960E	Alternating Tree (2300) (Tree DP + Combination + Contribution)	2021/07/22
386C	Diverse Substrings (2000) (Two Pointer)	2021/07/23
386D	Game with Points (2100) (Shortest Path)	2021/07/23
609E	Minimum spanning tree for each edge (2100) (MST + Thinking + LCA)	2021/07/24
900D	Unusual Sequences (2000) (Combination + Math)	2021/07/25
900C	Remove Extra One (1700) (Thinking + Left/Right DP)	2021/07/25
1270G	Subset with Zero Sum (2700) (Thinking + Graph + Sort + Math)	2021/07/25
1551D2	D2 - Domino (hard version) (2100) (Constructive)	2021/07/26
1551E	Fixed Points (2000) (DP + Binary Search)	2021/07/26
1551F	Equidistant Vertices (2200) (DP + Tree)	2021/07/26
1551B2.	Wonderful Coloring - 2 (1400) (Greedy + Binary Search)	2021/07/26
1542D	Priority Queue (2200) (DP + Contribution)	2021/07/27
514C	Watto and Mechanism (2000) (String Polynomial Hash)	2021/07/27
514D	R2D2 and Droid Army (2000) (Two Pointer + Segment Tree)	2021/07/28
514E	Darth Vader and Tree (2200) (Matrix + DP)	2021/07/28
519D	A and B and Interesting Substrings (1800) (Prefix Sum)	2021/07/29
519E	A and B and Lecture Rooms (2100) (Tree + LCA)	2021/07/29
983B	XOR-pyramid (1800) (Interval DP)	2021/07/29
1554D	Diane (1800) (Constructive + Thinking)	2021/07/30
1554B	Cobb (1700) (Submask + DP)	2021/07/30
165E	Compatible Numbers (2200) (Submask + DP + Bitmask)	2021/07/30
160D	Edges in MST (2300) (Graph + MST + Tarjan)	2021/07/31
55D	Beautiful numbers (2500) (Digit DP)	2021/08/01
899E	Segments Removal (2000) (UF + Double LinkedList)	2021/08/01
899D	Shovel Sale (1800) (Math + Thinking)	2021/08/01
899F	Letters Removing (2100) (BinarySearch + Fenwick)	2021/08/02
687C	The Values You Can Make (1900) (背包DP)	2021/08/02
472D	Design Tutorial: Inverse the Problem(1900) (MST + Tree + Greedy)	2021/08/03

上班了！！

#	Title	Date
665E	Beautiful Subarrays (2100) (Trie + XOR)	2021/08/03
665D	Simple Subset (1800) (Constructive + 打表)	2021/08/04
803F	Coprime Subsequences (2000) (DP + 容斥 + Number Theory)	2021/08/04
675D	Tree Construction (1800) (Binary Search Tree + Observation)	2021/08/05
675E	Trains and Statistic (2300) (DP + Greedy + Segment Tree)	2021/08/05
600C	Make Palindrome (1800) (Greedy + Constructive)	2021/08/06
675C	Money Transfers (2100) (Thinking + Prefix Sum + Transfer)	2021/08/06
475D	CGCDSSQ (2000) (GCD + Sparse Table)	2021/08/06
965D	Single-use Stones (1900) (Thinking + Two Pointer + Greedy)	2021/08/07
965E	Short Code (2200) (Trie + Greedy + 启发式合并)	2021/08/07
920F	SUM and REPLACE (2000) (LinkedList + UF + Fenwick)	2021/08/08
1508B	Almost Sorted (1800) (Observation + Construtive + Math)	2021/08/09
920E	Connected Components? (2100) (Graph)	2021/08/09
963B	Destruction of a Tree (2000) (Tree)	2021/08/10
1557C	Moamen and XOR (1700) (Combination)	2021/08/10
1555E	Boring Segments (2100) (Seg + Range Update)	2021/08/11
914C	Travelling Salesman and Special Numbers (1800) (Digit DP)	2021/08/12
453B	Little Pony and Harmony Chest (2000) (Bitmask DP)	2021/08/13
893D	Credit Card (1900) (Greedy)	2021/08/13
700B	Connecting Universities (1800) (Greedy + Tree)	2021/08/14
486E	LIS of Sequence (2200) (DP + Implementation)	2021/08/14
486D	Valid Sets (2100) (Tree + Combination + DP)	2021/08/14
459D	Pashmak and Parmida's problem (1800) (Fenwick Tree)	2021/08/14
459C	Pashmak and Buses (1900) (Greedy + Constructive)	2021/08/14
459E	Pashmak and Graph (1900) (DP)	2021/08/15
785E	Anton and Permutation (2200) (分块 + 逆序对)	2021/08/15
327C	Magic Five (1700) (Geometric Progression)	2021/08/16
1555D	Say No to Palindromes (1600) (Observation + Brute Force + Prefix Sum)	2021/08/16
1132F	Clear the String (2000) (区间 DP)	2021/08/17
1132E	Knapsack (2300) (DP + 背包 + 拆背包)	2021/08/17
670E	Correct Bracket Sequence Editor (1700) (LinkedList)	2021/08/18
670F	Restore a Number (2300) (Constructive)	2021/08/18
118E	Bertown roads (2000) (Graph + Tarjan + SCC)	2021/08/19
1560E	Polycarp and String Transformation (1800) (Sort + Binary Search + Construtive)	2021/08/19
1560F2	Nearest Beautiful Number (hard version) (2100) (Greedy + Construtive)	2021/08/19
1553F	Pairwise Modulo (2300) (Fenwick + Math + Thinking)	2021/08/21
1415E	New Game Plus! (2200) (Thinking Greedy)	2021/08/22
1553E	Permutation Shift (2100) (Thinking + Observation)	2021/08/23
797E	Array Queries (2000) (DP + Brute Force)	2021/08/24
463D	Gargari and Permutations(1900) (DP )	2021/08/25
808D	Array Division (1900) (Binary Search + Prefix Sum )	2021/08/25
463E	Caisa and Tree (2100) (Tree )	2021/08/25
891B	Gluttony (2000) (Constructive )	2021/08/26
859E	Desk Disorder (2100) (Combination + Tree + Graph )	2021/08/27
911G	Mass Change Queries (2500) (Segment Tree Tag )	2021/08/28
1051F	The Shortest Statement (2400) (LCA + Shortest Path + Tree + Thinking )	2021/08/28
999D	Equalize the Remainders (1900) (Greedy + TreeSet )	2021/08/29
999E	Reachability from the Capital (2000) (Graph)	2021/08/29
999F	Cards and Joy (2000) (DP)	2021/08/30
59E	Shortest Path (2000) (Shortest Path)	2021/08/30
59D	Team Arrangement (2000) (Implementation + Greedy + Thinking)	2021/08/31
201C	Fragile Bridges(2000) (Left-Right DP + Thinking + Sort)	2021/09/01
1030E	Vasya and Good Sequences (2000) (Thinking + Brute Force + Bit)	2021/09/02
729E	Subordinates (1900) (Greedy)	2021/09/02
1438D	Powerful Ksenia (2200) (Thinking)	2021/09/03
597C	Duff in the Army (2200) (LCA)	2021/09/03
195E	Building Forest (2000) (UF + Tree) (Thumb)	2021/09/04
933B	A Determined Cleanup (2000) (Math + Constructive) (Thumb)	2021/09/05
980E	The Number Games (2200) (Tree + Sparse + Greedy) (Thumb)	2021/09/05
846F	Random Query (1800) (Two Pointer)	2021/09/06
622E	Ants in Leaves (2200) (Tree + Thinking + Greedy)	2021/09/06
1244E	Minimizing Difference (2000) (Two Pointer + Greedy)	2021/09/07
1244D	Paint the Tree (1800) (DP + Tree)	2021/09/07
1244C	The Football Season (2000) (Math + Brute Force)	2021/09/08
1567F	One-Four Overload (2700) (Thinking + Observation + Constructice)	2021/09/09
1567E	Non-Decreasing Dilemma (2200) (Segment Tree + Divide Conquer)	2021/09/09
432D	Prefixes and Suffixes (2000) (KMP + DP)	2021/09/10
432E	Square Tiling (2300) (Constructive + Greedy)	2021/09/11
842C	Ilya And The Tree (2000) (DP Set)	2021/09/11
842D	Vitya and Strange Lesson (2000) (Trie + Bitmask + Thinking)	2021/09/12
1146F	Leaf Partition (2500) (Hard DP)	2021/09/12
1567D	Expression Evaluation Error (2000) (Greedy + Constructive)	2021/09/12
342E	Xenia and Tree (2400) (Centroid Decomposition)	2021/09/13
354C	Vasya and Beautiful Arrays (2100) (Thinking + Math Mod)	2021/09/14
1216F	Wi-Fi (2100) (Line DP + Segment Tree)	2021/09/14
1216E2	Numerical Sequence (hard version) (2200) (Binary Search + Math)	2021/09/14
1154G	Minimum Possible LCM (2200) (Brute Force, LCM)	2021/09/15
1154F	Shovels Shop (2100) (DP)	2021/09/15
1363E	Tree Shuffling (2000) (Tree + Greedy)	2021/09/16
1363F	Rotating Substrings (2600) (Hard DP)	2021/09/16
229D	Towers (2100) (DP + Two Pointer)	2021/09/17
813E	Army Creation (2200) (Thinking + Persistant Tree)	2021/09/17
813F	Bipartite Checking (2500) (Dynamic Connectivity + Online Bipartile checking)	2021/09/19
1204D2	D2 - Kirk and a Binary String (hard version)(2100) (Observation)	2021/09/19
1070A	Find a Number(2200) (Shortest Path)	2021/09/19
1303E	Erase Subsequences(2200) (DP + Thinking)	2021/09/19
877D	Olya and Energy Drinks (2100) (BFS + Thinking)	2021/09/20
877E	Danil and a Part-time Job (2000) (Tree + Segment Tree Push)	2021/09/20
75D	Big Maximum Sum (2000) (Left Right DP)	2021/09/21
833B	The Bakery (2200) (DP + Seg push down)	2021/09/22
196B	Infinite Maze (2000) (Graph + Thinking + Matrix)	2021/09/23
633D	Fibonacci-ish (2000) (Brute Force)	2021/09/24
633F	The Chocolate Spree(2600) (Tree DP)	2021/09/25
1530E	Minimax (2100) (Construvtice + String)	2021/09/25
1215E	Marbles (2200) (Bitmask DP)	2021/09/26
1176F	Destroy it! (2100) ( DP)	2021/09/26
1176E	Cover it! (1700) ( BFS)	2021/09/27
1176D	Recover it! (1800) ( Greedy + Sort)	2021/09/27
954G	Castle Defense (2000) (Binary Search + Two Pointer)	2021/09/28
543B	Destroying Roads (2100) (Shortes Path + Thinking) (Thumb)	2021/09/29
617E	XOR and Favorite Number (2200) (莫队 + Prefix)	2021/09/29
353D	Queue (2000) (观察)	2021/09/30
893E	Counting Arrays (2000) (Combination)	2021/09/30
369E	Valera and Queries(2200) (offline + Fenwick + Thinking + Line)	2021/09/30
369D	Valera and Fools (2200) (Thinking + Shortest Path + DP)	2021/09/30
362C	Insertion Sort (1900) ( DP + Prefix)	2021/10/01
369C	Valera and Elections (1600) (Tree)	2021/10/01
362E	Petya and Pipes (2300) (mcmf)	2021/10/01
546E	Soldier and Traveling (2100) (flow + Graph Construct)	2021/10/03
546D	Soldier and Number Game (1700) (打表 + Prefix Sum)	2021/10/04
1213E	Two Small Strings (1900) (Constructive + Brute Force)	2021/10/05
1213F	Unstable String Sort (2100) (Direct Graph Tarjan + Constructive)	2021/10/05
1213D2	Equalizing by Division (hard version) (1600) (Sort)	2021/10/07
629C	Famil Door and Brackets (2000) (DP + Bracket)	2021/10/07
777E	Hanoi Factory (2000) (DP + Seg + sort)	2021/10/08
1592E	Bored Bakry (2400) (Two Pointer + Bit + Prefix + Thinking)	2021/10/08
552E	Vanya and Brackets (2100) (Expression Tree + Observation)	2021/10/09
552C	Vanya and Scales (1900) (进制)	2021/10/10
128D	Numbers (2000) (Constructive + list)	2021/10/11
128B	String (2100) (Constructive + kth substring)	2021/10/12
1600E	Array Game (1900) (Thinking + Game)	2021/10/13
264C	Choosing Balls (2000) (DP)	2021/10/14
1579G	Minimal Coverage (2200) (DP + Thinking)	2021/10/15
1579E2	Array Optimization by Deque (1700) (Fenwick)	2021/10/15
1579F	Array Stabilization (AND version)(1700) (BFS + Observation)	2021/10/16
1593F	Red-Black Number (2100) (DP)	2021/10/16
1593G	Changing Brackets (2200) (Obsetvation)	2021/10/17
474E	Pillars (2000) (Segment Tree + DP + TreeSet)	2021/10/17
474D	Flowers (1700) (DP)	2021/10/18
474F	Ant colony (2100) (Segment Tree + GCD + Binary Search)	2021/10/18
1593D2	Half of Same (1900) (Time + Thinking)	2021/10/18
1209G1	Into Blocks (easy version) (2000) (Line + Greedy)	2021/10/19
1550C	Manhattan Subarrays (1700) (Observation + Brute Force)	2021/10/20
349B	Color the Fence (1700) (Greedy)	2021/10/20
349C	Mafia(1600) (Binary Search + Thinking)	2021/10/20
903E	Swapping Characters (2200) (Brute Force + Observation)	2021/10/21
1575L	Longest Array Deconstruction(2100) (DP + LIS)	2021/10/22
1575H	Holiday Wall Ornaments(2200) (DP + KMP)	2021/10/23
1575I	Illusions of the Desert (2300) (Tree + LCS + Tree Euler + Tree Path Query)	2021/10/23
1575G	GCD Festival (2200) (GCD + PHI)	2021/10/24
598E	Chocolate Bar (2000) (DP)	2021/10/24
895B	XK Segments (1700) (Binary Search)	2021/10/24
862C	Mahmoud and Ehab and the xor (1900) (Xor + Constructive)	2021/10/25
478D	Red-Green Towers (2000) (DP)	2021/10/25
478C	Table Decorations (1800) (Greedy)	2021/10/26
1129B	Wrong Answer (2000) (Constructice + Math)	2021/10/26
109D	Lucky Sorting (2000) (Constructice + Brute Force)	2021/10/27
446C	DZY Loves Fibonacci Numbers (2400) (Segment Tree push down + Fib Number Property)	2021/10/27
446B	DZY Loves Modification (2000) (Greedy)	2021/10/27
1373F	Network Coverage (2400) (Binary Search)	2021/10/27
1373E	Sum of Digits (2200) (Greedy + Constructive)	2021/10/28
1003E	Tree Constructing (2100) (Tree + Constructive)	2021/10/28
1003F	Abbreviation (2200) (DP)	2021/10/28
337D	Book of Evil (2000) (Tree Re-Range)	2021/10/29
337E	Divisor Tree (2200) (Brute Foce)	2021/10/29
22E	Scheme (2300) (Graph + Constructive)	2021/10/30
1140E	Palindrome-less Arrays (2200) (DP + Combination + Observation)	2021/10/30
1647D	Coins and Queries (1600) (Greedy)	2021/10/31
353B	Two Heaps (1900) (Greedy + Thinking)	2021/10/31
274B	Zero Tree (1800) (Tree DP )	2021/10/31
296B	Yaroslav and Two Strings(2000) ( DP )	2021/11/01
1311D	Three Integers (2000) ( Brute Force + 打表 )	2021/11/02
886D	Restoration of string(2000) ( Graph + Construtive + String )	2021/11/02
641E	Little Artem and Time Machine (2000) ( Fenwick + offline )	2021/11/02
1105E	Helping Hiasat (2200) ( Maximum Independent Set + DP )	2021/11/03
1304E	1-Trees and Queries (2000) ( LCA )	2021/11/04
543D	Road Improvement (2300) ( Tree DP + Left/Right DP )	2021/11/04
1558C	Bottom-Tier Reversals (2000) ( Constructive )	2021/11/04
623B	Array GCD (2300) ( DP )	2021/11/05
494B	Obsessive String (2000) ( DP + KMP + Prefix )	2021/11/05
620D	Professor GukiZ and Two Arrays (2200) ( Two Pointer )	2021/11/05
1005E2	Median on Segments (General Case Edition) (2400) ( Bound + Prefix )	2021/11/06
1005F	Berland and the Shortest Paths (2100) ( Graph + BFS )	2021/11/06
1582F2	Korney Korneevich and XOR (hard version) (2400) ( Thinking )	2021/11/07
1582E	Pchelyonok and Segments(2000) ( DP )	2021/11/07
1582D	Vupsen, Pupsen and 0 (1600) ( Constructive )	2021/11/07
301D	Yaroslav and Divisors (2200) ( Thinking + Inteval )	2021/11/08
762D	Maximum path (2300) ( DP + State Representation )	2021/11/09
258C	Little Elephant and LCM (2000) ( Binary Search )	2021/11/09
490E	Restoring Increasing Sequence (2000) ( Constructive + Greedy)	2021/11/09
713C	Sonya and Problem Wihtout a Legend (2300) (DP + Thinking)	2021/11/10
615D	Multipliers (2000) (Combination + Math)	2021/11/10
1268C	K Integers (2300) (Thinking)	2021/11/11
476E	Dreamoon and Strings (2200) (Thinking + DP)	2021/11/12
274D	Lovely Matrix (2200) (Graph Model + Topo)	2021/11/12
743E	Vladik and cards (2200) (Bitmask DP + Binary Search)	2021/11/12
1349B	Orac and Medians (2000) (Constructive + Thinking + Observation)	2021/11/13
1187C	Vasya And Array(1800) (Constructive + Line Sweep)	2021/11/14
238B	Boring Partition (1800) (Constructive + Greedy)	2021/11/14
1136E	Nastya Hasn't Written a Legend (2200) (Segment SetTo + Math)	2021/11/15
533E	Correcting Mistakes (1800) (Observation)	2021/11/15
1257F	Make Them Similar(2400) (Meet In Middle + Hash)	2021/11/16
946E	Largest Beautiful Number (2200) (Constructive + Greedy)	2021/11/16
255D	Mr. Bender and Square (1800) (Binary Search + Math)	2021/11/16
1237D	Balanced Playlist (2000) (MonoQueue)	2021/11/17
1245F	Daniel and Spring Cleaning (2300) (数位DP + 二维容斥)	2021/11/17
1000F	One Occurrence (2400) (莫队，主席树)	2021/11/18
67A	Partial Teacher (1800) (Direct Graph + DP)	2021/11/18
1556E	Equilibrium(2200) (Thinking + Bracket + Segment Tree)	2021/11/18
1220F	Gardener Alex (2700) (Cartesian Tree + Binary Search + Segment Tree + Tree)	2021/11/19
864E	Fire (2000) (DP)	2021/11/19
1101G	(Zero XOR Subset)-less (2300) (线性基)	2021/11/20
845G	Shortest Path Problem? (2300) (线性基 + Graph + Thinking)	2021/11/20
1165F2	Microtransactions (hard version) (2000) (BinarySearch + Thinking)	2021/11/20
1295E	Permutation Separation (2200) (Segment Tree pushDown + Thinking)	2021/11/21
336D	Vasily the Bear and Beautiful Strings (2100) (Combiniation + Thinking)	2021/11/21
788B	Weird journey (2100) (Euler Path + Thinking)	2021/11/21
766E	Mahmoud and a xor trip (2100) (Tree DP)	2021/11/22
852E	Casinos and travel(2100) (Thinking)	2021/11/23
1120C	Compress String (2100) (DP)	2021/11/24
570E	Pig and Palindromes (2300) (DP)	2021/11/25
773C	Prairie Partition (2200) (Greedy + Constructive)	2021/11/26
786C	Till I Collapse (2400) (Persistant Tree)	2021/11/27
1601C	Optimal Insertion (2300) (Divide Conquer)	2021/11/28
1355E	Restorer Distance (2100) (Tenery Search)	2021/11/29
314B	Sereja and Periods(2000) (Brute Force)	2021/11/29
333D	Characteristics of Rectangles (2100) (Binary Search + 鸽子)	2021/11/29
721D	Maxim and Array (2000) (Greedy + Math)	2021/11/30
914E	Palindromes in a Tree (2400) (点分治)	2021/12/01
253D	Table with Letters - 2(2000) (Two Pointer)	2021/12/02
600E	Lomsat gelral (2300) (启发合并)	2021/12/02
985E	Pencils and Boxes (2100) (DP + Fenwick)	2021/12/03
985C	Liebig's Barrels (1500) (Greedy)	2021/12/03
1614D2	Divan and Kostomuksha (hard version) (2300) (DP)	2021/12/03
1225E	Rock Is Push (2200) (DP + Thinking)	2021/12/03
865D	Buy Low Sell High (2400) (Greedy + Heap)	2021/12/03
1326E	Bombs (2400) (Thinking + Seg push down)	2021/12/04
986C	AND Graph (2500) (Graph)	2021/12/04
1327F	AND Segments (2500) (DP + Thinking)	2021/12/05
703D	Mishka and Interesting sum (2100) (Fenwick + Thinking)	2021/12/06
850B	Arpa and a list of numbers (2100) (Math + 打表)	2021/12/07
1527E	Partition Game (2500) (DP + Thinking + Seg push down)	2021/12/08
839D	Winter is here (2200) (容斥 + Combination)	2021/12/08
734E	Anton and Tree (2100) (Tree)	2021/12/09
734F	Anton and School(2500) (Thinking + Constructive + Math)	2021/12/09
848C	Goodbye Souvenir(2600) (CDQ 分支)	2021/12/14
1618G	Trader Problem (2200) (UF + Sort)	2021/12/16
1618E	Singers' Tour (1700) (MAth + Constructive)	2021/12/18
323B	Tournament-graph (2200) (Constructive)	2021/12/20
1399F	Yet Another Segments Subset (2300) (区间DP)	2021/12/21
85D	Sum of Medians (2300) (Seg push + Thinking)	2021/12/22
1349C	Orac and Game of Life (2000) (Graph + Thinking)	2021/12/23
220C	Little Elephant and Shifts (2100) (Two Heap Moving + Thinking)	2021/12/23
1336C	Kaavi and Magic Spell(2200) (区间DP + Thinking)	2021/12/25
1168C	And Reachability (2200) (DP)	2021/12/25
1148E	Earth Wind and Fire(2300) (Greedy + Thinking)	2021/12/26
280B	Maximum Xor Secondary (1800) (Monotic Stack)	2021/12/26
1225D	Power Products (1800) (Math + Hash)	2021/12/26
1203F2	Complete the Projects (hard version) (2300) (DP + Greedy + Sort)	2021/12/27
811C	Vladik and Memorable Trip (1900) (DP)	2021/12/28
134B	Pairs of Numbers (1900) (Math + Brute Force)	2021/12/30
134C	Swaps (2200) (Greedy)	2021/12/30
1166D	Cute Sequences (2200) (Greedy + Math + Constructive)	2021/12/30
451D	Cute Count Good Substrings (2000) (Math)	2021/12/31
451E	Devu and Flowers (2300) (容斥 + Lucas 定理)	2021/12/31
403D	Beautiful Pairs of Numbers (2200) (DP + Combination)	2021/01/01
1367F1	Flying Sort (Easy Version) (2100) (DP + Thinking)	2021/01/03
1367F2	Flying Sort (Hard Version) (2400) (DP + Thinking)	2021/01/03
1061D	TV Shows (2000) (Sort + Greedy)	2021/01/04
1251E2	Voting (Hard Version) (2400) (Greedy)	2021/01/05
620E	New Year Tree (2100) (Seg push + Tree + Bit)	2021/01/05
691F	Couple Cover (2200) (Brute Force + Prefix)	2021/01/06
837E	Vasya's Function (2100) (Thinking + Math)	2021/01/06
837D	Round Subset (2100) (DP)	2021/01/06
1316E	Team Building (2300) (Bitmask DP + Thinking)	2021/01/06
1621D	The Winter Hike (2100) (Thinking)	2021/01/06
627C	Package Delivery (2200) (Greedy) (Thumb)	2021/01/07
1253E	Antenna Coverage (2200) (DP) (Thumb)	2021/01/07
821D	Okabe and City (2200) (Graph Building + Shortest Path) (Thumb)	2021/01/08
1188B	Count Pairs (2300) (Math + Equation)	2021/01/09
1107E	Vasya and Binary String (2400) (区间DP)	2021/01/09
1542E1	Abnormal Permutation Pairs (easy version) (2400) (DP + Combination)	2021/01/12
1542E2	Abnormal Permutation Pairs (hard version) (2700) (DP + Combination + Prefix Sum)	2021/01/12
632D	Longest Subsequence (2100) (LCM + Brute Force)	2021/01/13
689D	Friends and Subsequences (2100) (Binary Search)	2021/01/13
689E	Mike and Geometry Problem (2000) (Combination + Lined Sweep) (Thumb)	2021/01/13
900E	Maximum Questions (2100) (DP + Thinking ) (Thumb)	2021/01/14
226D	The table (2100) (Constructive + Thinking ) (Thumb)	2021/01/14
301B	Yaroslav and Time (2100) (Shortest Path + Thinking ) (Thumb)	2021/01/15
1220E	Tourism (2200) (无向图缩点 + Tree DP ) (Thumb)	2021/01/16
722D	Generating Sets (1900) (Greedy)	2021/01/16
510D	Fox And Jumping (1900) (GCD + DP) （Thumb）	2021/01/16
894C	Marco and GCD Sequence (1900) (Constructive)	2021/01/17
817D	Imbalanced Array (1900) (Stack) (Thumb)	2021/01/17
1238D	AB-string (1900) (Thinking)	2021/01/18
1197D	Yet Another Subarray Problem (1900) (DP)	2021/01/20
1076E	Vasya and a Tree (1900) (Fenwick Tree)	2021/01/20
1000D	Yet Another Problem On a Subsequence (1900) (DP)	2021/01/21
796C	Bank Hacking (1900) (Thinking + Segment Tree)	2021/01/21
746E	Numbers Exchange (1900) (Greedy + Constructive)	2021/01/21
982D	Shark (1900) (Union Find)	2021/01/23
754D	Fedor and coupons (2100) (Sort)	2021/01/25
796D	Police Stations (2100) (Thinking + Graph)	2021/01/26
748E	Santa Claus and Tangerines (2100) (Thinking)	2021/01/26
1146D	1146D (2100) (Math + GCD)	2021/01/26
283C	Coin Troubles (2100) (DP + Thinking)	2021/01/27
1254B2	Send Boxes to Alice (Hard Version)(2100) (Thinking)	2021/01/27
1207F	Remainder Problem (2100) (Thinking + Time)	2021/01/28
793D	Presents in Bankopolis(2100) (DP)	2021/01/28
165D	Beard Graph (2100) (LCA + Fenwick)	2021/01/29
1056E	Check Transcription (2100) (Rolling Hash)	2021/01/29
1163D	Mysterious Code (2100) (kmp + dp)	2021/01/29
894E	Ralph and Mushrooms(2100) (Tarjan Direct)	2021/01/30
1364D	Ehab's Last Corollary (2100) (Graph + DFS 最小环)	2021/01/31
1322B	Present (2100) (Math + Bit + Two Pointer)	2021/01/31
992D	Nastya and a Game (2100) (Math + Brute Force)	2021/02/01
1092D1	Great Vova Wall (Version 1) (2200) (Thinking + Greedy)	2021/02/01
1092D2	Great Vova Wall (Version 2) (2200) (Thinking + Greedy)	2021/02/01
1198D	Rectangle Painting 1 (2300) (DP)	2021/02/01
1073E	Segment Sum (2300) (Digit DP)	2021/02/02
1238E	Keyboard Purchase (2200) (Bitmask DP)	2021/02/02
1093F	Vasya and Array (2400) ( DP + 容斥)	2021/02/03
1208E	Let Them Slide (2200) ( Thinking)	2021/02/04
878B	Teams Formation (2300) ( Thinking + Constructive)	2021/02/04
1630C	Paint the Middle(2200) ( Thinking + Interval)	2021/02/04
1630D	Flipping Range (2400) ( DP + Thinking)	2021/02/06
1110E	Magic Stones (2200) ( 差分)	2021/02/06
868D	Huge Strings (2200) ( Brute Force)	2021/02/06
958E2	Guard Duty (medium) (2200) ( DP)	2021/02/07
920G	List Of Integers (2200) ( 容斥)	2021/02/08
1632D	New Year Concert (2000) ( Two Pointer + Seg + GCD)	2021/02/09
1637E	Best Pair (Brute Force + Time)	2021/02/13
756C	Nikita and stack (2200) (Thinking + Segment Tree)	2021/02/14
1632E1	Distance Tree (easy version) (2400) (Thinking + Tree + Brute Force)	2021/02/14
1333F	Kate and imperfection (2200) (Thinking + 打表)	2021/02/15
1622D	Shuffle (2000) (Thinking + Combination)	2021/02/15
383D	Antimatter (2300) (DP)	2021/02/16
808E	Selling Souvenirs (2300) (Tenary Search)	2021/02/16
1622E	Math Test (2200) (Thinking + Brute Force)	2021/02/16
1638E	Colorful Operations (2400) (Thinking + Interval Problem)	2021/02/19
1616E	Lexicographically Small Enough(2200) (Fenwick)	2021/02/20
915D	Almost Acyclic Graph (2200) (Graph + Thinking)	2021/02/21
915E	Physical Education Lessons (2300) (Interval)	2021/02/21
1181D	Irrigation (2200) (Sorting + Segment Tree)	2021/02/21
1228E	Another Filling the Grid (2300) (DP + Combination)	2021/02/22
847D	Dog Show (2200) (Heap + Greedy)	2021/02/22
1419E	Decryption (2100) (Math + Constructive)	2021/02/22
1370E	Binary Subsequence Rotation (2100) (Thinking + Constructive)	2021/02/23
489F	Special Matrices (2100) (DP + Combination)	2021/02/24
799D	Field expansion (2100) (DP)	2021/02/24
1365F	1365F (2100) (Constructive + Thinking)	2021/02/25
1167F	Scalar Queries (2300) (Combination)	2021/02/26
1389D	Scalar Queries (2100) (Implementation)	2021/02/26
1398E	Two Types of Spells (2200) (Seg + Thinking)	2021/02/27
895D	String Mark (2100) (Com + String prefix)	2021/02/28
1418D	Trash Problem (2100) (TreeMap)	2021/03/01
1158C	Permutation recovery (2100) (Graph + Constructive)	2021/03/01
1271E	Common Number (2100) (Binary Search + Math)	2021/03/02
343D	Water Tree (2100) (Tree + Seg push)	2021/03/02
1360H	Binary Median (2100) (Binary Search)	2022/03/02
976E	Well played! (2100) (Greedy)	2022/03/02
1231E	Middle-Out (2200) (Greedy + Constructive)	2022/03/02
1557D	Ezzat and Grid (2200) (Seg push + DP)	2022/03/03
1004D	Sonya and Matrix (2300) (Thinking + Math Equation + Constructive)	2022/03/03
979D	Kuro and GCD and XOR and SUM (2200) (Trie)	2022/03/04
1638D	Big Brush (2000) (Constructive)	2022/03/04
1607G	Banquet Preparations 1 (2200) (Greedy)	2022/03/04
1646E	Power Board (2200) (Math + DP)	2022/03/04
1646D	Weight the Tree (2000) (Tree + DP)	2022/03/05
1607H	Banquet Preparations 2 (2200) (Greedy)	2022/03/05
1552F	Telepanting (2200) (DP + Thinking + Math)	2022/03/05
1467D	Sum of Paths (2200) (DP + Combination)	2022/03/06
1355F	Robots on a Grid (2200) (Graph + Thinking)	2022/03/07
616E	Sum of Remainders (2200) (Math)	2022/03/07
1526D	Kill Anton (2200) (Thinking)	2022/03/07
1305E	Kuroni and the Score Distribution (2200) (Constructive)	2022/03/08
1580C	Train Maintenance (2200) (Thinking + Brute Force)	2022/03/08
559C	Gerald and Giant Chess (2200) (Combination + DP + 容斥 + Unique Path 升级)	2022/03/09
906B	Seating of Students (2200) (Constructive)	2022/03/09
507D	The Maths Lecture (2200) (Digit DP)	2022/03/10
1650G	Counting Shortcuts (2100) (Shortest Path + DP)	2022/03/10
1650F	Vitaly and Advanced Useless Algorithms (2200) (DP)	2022/03/11
1650E	Rescheduling the Exam (1900)	2022/03/11
1580B	Mathematics Curriculum (2600) (Permutation DP + Combination)	2022/03/13
912E	Prime Gift (2400) (Brute Force + Meet in Middle)	2022/03/13
817F	MEX Queries (2300) (Segment Update + rever a bit rangg + Cpp) (Thumb)	2022/03/15
1342E	Placing Rooks (2300) (Com + 容斥) (Thumb)	2022/03/15
1304F1	Animal Observation (easy version) (2300) (DP)	2022/03/15
1304F2	Animal Observation (Hard version) (2400) (DP + Monoqueue + Thinking)	2022/03/15
1442C	Graph Transpositions (2400) (Thinking + Shortest Path)	2022/03/16
1149B	Three Religions (2200) (DP + Thinking)	2022/03/17
1603C	Extreme Extension (2300) (DP + Thinking + Math)	2022/03/17
1037E	Trips (2200) (Graph)	2022/03/18
1132G	Greedy Subsequences (2400) (Seg push + Tree + DP)	2022/03/18
830C	Bamboo Partition (2300) (除法分块 + Math)	2022/03/19
919E	Congruence Equation (2100) (费马小定理)	2022/03/21
1500B	Two chandeliers (2200) (CRT and EXCRT)	2022/03/22
364B	Free Market (2200) (DP + Greedy)	2022/03/23
1380E	Merging Towers (2300) (启发式合并)	2022/03/23
1654E	Arithmetic Operations (2300) (Brute Force + Time Complexity)	2022/03/23
922E	Birds (2200) (DP + Monoqueue)	2022/03/24
618D	Hamiltonian Spanning Tree (2200) (Greedy + Tree)	2022/03/25
618F	Double Knapsack (3000) (鸽子原理)	2022/03/25
1093E	Intersection of Permutations (2400) (CDP 分支二维)	2022/03/25
955C	Sad powers (2100) (binary search + 预处理)	2022/03/26
1658D2	388535 (Hard Version) (2300) (Trie)	2022/03/27
1657E	Star MST (2200) (MST + DP + Combination)	2022/03/29
1656E	Equal Tree Sums (2200) (Constructive)	2022/03/30
707D	Persistent Bookcase (2200) (DFS)	2022/03/31
1585E	Frequency Queries (2400) (Seg)	2022/03/31
1619H	Permutation and Queries (2400) (分块)	2022/04/01
1660F2	Promising String (hard version) (2100) (Fenwick + Thinking)	2022/04/03
1100E	Andrew and Taxi (2200) (Graph)	2022/04/04
1343F	Restore the Permutation by Sorted Segments (2400) (Constructive)	2022/04/04
220E	Little Elephant and Inversions (2400) (Two Pointer + 逆序对)	2022/04/04
946G	Almost Increasing Array (2500) (DP + LIS)	2022/04/05

分类

DP

1133E.K Balanced Teams (1800) (DP)
1110D Jongmah (2200) （DP + Greedy）
176B. Word Cut (1700) (DP + Observation)
1472F. New Year's Puzzle (2100) (DP)
1513C. Add One (1600) （DP）
1517D. Explorer Space (1800) （DP）
977F. Consecutive Subsequence (1700) (DP)
313D. Ilya and Roads (2100) (DP)
66E. Petya and Post(2000) (DP + Thinking)
1525D. Armchairs (1800) (DP)
31E. TV Game (2400) (DP)
1529D. Kavi on Pairing Duty (1700) (Thinking + DP)
1527C. Sequence Pair Weight (1600) (DP)
279E.Beautiful Decomposition(1900) (Bit + DP)
46E. Comb (1900) ( DP)
988F. Rain and Umbrellas (2100) ( DP)
1536C. Diluc and Kaeya (1500) ( DP + HashMap)
1066F. Yet another 2D Walking (2100) (DP + Math)
1487F.Ones (2900) (DP + Observation)
571B. Minimization (2000) (DP + k skip)
466D. Increase Sequence (2100) (DP)
1155D. Beautiful Array (1900) (DP + Kadane)
626F. Group Projects (2400) (DP + Thinking)
1188C. Array Beauty (2500) (DP + Brute Force + Time Complexity)
895C. Square Subsets (2000) (DP + Combination + BitMask) C(n,0) + C(n,2) + ... == C(n,1) + C(n,3) = C(n,5) + ... == 2^(n-1)
1025D. Recovering BST (2000) (TreeDP)
360B. Levko and Array (2000) (DP)
597C.Subsequences (1900) (DP + Fenwick)
597B.Restaurant (1600) (DP + Binary Search)
1551E.Fixed Points (2000) (DP + Binary Search)
486E.LIS of Sequence (2200) (DP + Implementation)
459E.Pashmak and Graph (1900) (DP)
797E. Array Queries (2000) (DP + Brute Force)
463D. Gargari and Permutations(1900) (DP )
999F.Cards and Joy (2000) (DP)
1244D.Paint the Tree (1800) (DP + Tree)
1146F.Leaf Partition (2500) (Hard DP)
1154F. Shovels Shop (2100) (DP)
229D. Towers (2100) (DP + Two Pointer)
1176F. Destroy it! (2100) ( DP)
629C.Famil Door and Brackets (2000) (DP + Bracket)
777E.Hanoi Factory (2000) (DP + Seg + sort)
264C. Choosing Balls (2000) (DP)
1579G. Minimal Coverage (2200) (DP + Thinking)
1593F.Red-Black Number (2100) (DP)
474E.Pillars (2000) (Segment Tree + DP + TreeSet)
598E.Chocolate Bar (2000) (DP)
1003F.Abbreviation (2200) (DP)
1140E.Palindrome-less Arrays (2200) (DP + Combination + Observation)
1582E.Pchelyonok and Segments(2000) ( DP )
762D.Maximum path (2300) ( DP + State Representation )
476E.Dreamoon and Strings (2200) (Thinking + DP)
864E.Fire (2000) (DP)
1120C.Compress String (2100) (DP)
570E.Pig and Palindromes (2300) (DP)
1225E.Rock Is Push (2200) (DP + Thinking)
1327F.AND Segments (2500) (DP + Thinking)
1367F1.Flying Sort (Easy Version) (2100) (DP + Thinking)
1367F2.Flying Sort (Hard Version) (2400) (DP + Thinking)
900E.Maximum Questions (2100) (DP + Thinking ) (Thumb)
1198D.Rectangle Painting 1 (2300) (DP)
383D.Antimatter (2300) (DP)

LCS Similar

1363F. Rotating Substrings (2600) (Hard DP)

LIS

1575L.Longest Array Deconstruction(2100) (DP + LIS)
946G.Almost Increasing Array (2500) (DP + LIS)

DP With Greedy Property

675E.Trains and Statistic (2300) (DP + Greedy + Segment Tree)

KnapSack

687C.The Values You Can Make (1900) (背包DP)
1132E.Knapsack (2300) (DP + 背包 + 拆背包)
478D.Red-Green Towers (2000) (DP)

DP Optimization I (Prefix on DP)

479E. Riding in a Lift (1900) (DP + Prefix Sum)

DP - Distinct Subsequence

1183H. Subsequences (hard version) (2000) ( DP + Distinct Subsequence )
314C. Sereja and Subsequences (2100) (DP + Distince Subsequence + Fenwick Tree)

DP Set

842C.Ilya And The Tree (2000) (DP Set)

Line/Interval DP

1216F.Wi-Fi (2100) (Line DP + Segment Tree)

Prefix/Left-Right DP

1185D.Extra Element (1700) (Prefix DP )
1278C. Berry Jam (1700) (DP + Left Right)
21C. Stripe 2 (2000) (Dp)
1474D. Cleaning (2200) (Thinking + Left/Right DP)
224D. Two Strings (1900) (left-right DP +Binary Search)
279C. Ladder (1700) (Segment Tree +Left-right DP)
1015E2.Stars Drawing (Hard Edition) (1900) (DP)
1066E. Binary Numbers AND Sum (1700) (Prefix)
466C. SNumber of Ways (1700) (DP + rihgt/prefix)
900C.Remove Extra One (1700) (Thinking + Left/Right DP)
519D.A and B and Interesting Substrings (1800) (Prefix Sum)
201C.Fragile Bridges(2000) (Left-Right DP + Thinking + Sort)
75D. Big Maximum Sum (2000) (Left Right DP)
362C. Insertion Sort (1900) ( DP + Prefix)

DP 转换/Optimize

1303E. Erase Subsequences(2200) (DP + Thinking)

Permutation DP

1580B.Mathematics Curriculum (2600) (Permutation DP + Combination)

树DP

161D. Distance in Tree (1800) (Tree DP )
1029E.Tree with Small Distances (2100) (Tree DP)
1092F. Tree with Maximum Cost (Tree DP)
1025D. Recovering BST (2000) (TreeDP)
633F. The Chocolate Spree(2600) (Tree DP)
274B.Zero Tree (1800) (Tree DP )
543D.Road Improvement (2300) ( Tree DP + Left/Right DP )
766E.Mahmoud and a xor trip (2100) (Tree DP)
1646D.Weight the Tree (2000) (Tree + DP)

Digit DP

55D.Beautiful numbers (2500) (Digit DP)
914C.Travelling Salesman and Special Numbers (1800) (Digit DP)
1073E.Segment Sum (2300) (Digit DP)

Bit DP

1185G1. Playlist for Polycarp (easy version) (2100) (Bitmask DP )
279D.The Minimum Number of Variables(2200) (Bit DP)
453B.Little Pony and Harmony Chest (2000) (Bitmask DP)
1215E. Marbles (2200) (Bitmask DP)
1316E.Team Building (2300) (Bitmask DP + Thinking)
1238E.Keyboard Purchase (2200) (Bitmask DP)

Submask DP (SOS)

1554B.Cobb (1700) (Submask + DP)
165E.Compatible Numbers (2200) (Submask + DP + Bitmask)

区间DP

1509C. The Sports Festival (1800) (DP)
983B.XOR-pyramid (1800) (Interval DP)
1132F.Clear the String (2000) (区间 DP)
1399F. Yet Another Segments Subset (2300) (区间DP)
1336C.Kaavi and Magic Spell(2200) (区间DP + Thinking)
1107E.Vasya and Binary String (2400) (区间DP + remove box)

DP + Monoqueue

1077F2.Pictures with Kittens (hard version) (2100) (DP + Monoqueue)
487B. Strip (2000) (DP + Monoqueue)
1304F2.Animal Observation (Hard version) (2400) (DP + Monoqueue + Thinking)

概率DP

540D. Bad Luck Island (1900) (DP)

String Match KMP + DP

1575H.Holiday Wall Ornaments(2200) (DP + KMP)
494B.Obsessive String (2000) ( DP + KMP + Prefix )
1163D.Mysterious Code (2100) (kmp + dp)

Contribution

1151E.Number of Components(2100) (Observation + Thinking + Contribution)
903D. Almost Difference (2200) (Contribution)
960E.Alternating Tree (2300) (Tree DP + Combination)
1542D.Priority Queue - 2 (2200) (DP + Contribution)

Kadane

1155D. Beautiful Array (1900) (DP + Kadane)

Matrix

621E. Wet Shark and Blocks (2000) (Matrix Exponent + DP)
450B. Jzzhu and Sequences (1300) (Matrix)
222E. Decoding Genome (1900) (DP + Matrix)
1151F.Sonya and Informatics (2300) (Matrix + DP + Probability) (Thunp)
514E.Darth Vader and Tree (2200) (Matrix + DP)

Greedy

540B. School Marks (1700) (Greedy )
1144G. Two Merged Sequences (2400) (Greedy) (Thumb)
1203F1. Complete the Projects (easy version) (2100) (Greedy + Sort) (Thump)
1508A. Binary Literature (1900) (Greedy) (Thumb)
313E. Ilya and Two Numbers (2300) (Greedy + Thinking + Sort)
45E. Director (2000) (Greedy + Implementation)
1294E. Obtain a Permutation (1900) (Implementation)
450E. Jzzhu and Apples (2500) (Greedy)
73B. Need For Brake (2000) (Greedy + Sort)
484D. Kindergarten (2400) (DP + Greedy + Observation)
509C.Sums of Digits (2000) (Constructive + Greedy)
1551B2.Wonderful Coloring - 2 (1400) (Greedy + Binary Search)
600C.Trains and Statistic (1800) (Greedy + Constructive)
965D.Single-use Stones (1900) (Thinking + Two Pointer + Greedy)
893D.Credit Card (1900) (Greedy)
1415E. New Game Plus! (2200) (Thinking Greedy)
999D. Equalize the Remainders (1900) (Greedy + TreeSet )
729E.Subordinates (1900) (Greedy)
1176D. Recover it! (1800) ( Greedy + Sort)
349B.Color the Fence (1700) (Greedy)
446B.DZY Loves Modification (2000) (Greedy)
353B.Two Heaps (1900) (Greedy + Thinking)
721D. Maxim and Array (2000) (Greedy + Math)
985C.Liebig's Barrels (1500) (Greedy)
627C.Package Delivery (2200) (Greedy) (Thumb)
976E.Well played! (2100) (Greedy)

Greedy : 后替换

1607G.Banquet Preparations 1 (2200) (Greedy)
1607H.Banquet Preparations 2 (2200) (Greedy)

Greedy : Number

1567D.Expression Evaluation Error (2000) (Greedy + Constructive)

Greedy+Heap

1260E. Tournament (2400) (Greedy + Heap)
865D.Buy Low Sell High (2400) (Greedy + Heap)
1061D.TV Shows (2000) (Sort + Greedy)
847D.Dog Show (2200) (Heap + Greedy)

Constructive

1185E.Polycarp and Snakes (2000) (Brute Force + Implementation )
1493C. K-beautiful Strings (2000) （Greedy + Constructive）
1234C. Pipes (1500) (Implementation)
66D. Petya and His Friends (1700) (Constructive)
125C. Hobbits' Party (1600) (Constructive)
45J. Planting Trees (1800) (Constructive)
1015D. Walking Between Houses (1600) (Constructive)
439C.Devu and Partitioning of the Array (1700) (Constructive)
414A. Mashmokh and Numbers (1500) (GCD (a,a+1) == 1)
911E. Stack Sorting (2000) (Constructive + Stack)
12E. Start of the session(2100) (Constructive)
359B. Permutations (1400) (Constructive)
1098B.Nice table (2100) (Constructive + Brute Force)
404C.Restore Graph (1800) (Constructive + Graph)
960C.Subsequence Counting (1700) (Constructive)
1551D2.D2 - Domino (hard version) (2100) (Constructive)
1554D.Diane (1800) (Constructive + Thinking)
665D.Simple Subset (1800) (Constructive + 打表)
1508B.Almost Sorted (1800) (Observation + Construtive + Math)
459C.Pashmak and Buses (1900) (Greedy + Constructive)
670F.Restore a Number (2300) (Constructive)
1560E. Polycarp and String Transformation (1800) (Sort + Binary Search + Construtive)
1560F2. Nearest Beautiful Number (hard version) (2100) (Greedy + Construtive)
891B. Gluttony (2000) (Constructive )
432E.Square Tiling (2300) (Constructive + Greedy)
1204D2. D2 - Kirk and a Binary String (hard version)(2100) (Observation)
1530E. Minimax (2100) (Construvtice + String)
1213E.Two Small Strings (1900) (Constructive + Brute Force)
128D.Numbers (2000) (Constructive + list)
128B.String (2100) (Constructive + kth substring)
862C.Mahmoud and Ehab and the xor (1900) (Xor + Constructive)
1129B.Wrong Answer (2000) (Constructice + Math)
109D.Lucky Sorting (2000) (Constructice + Brute Force)
1373E.Sum of Digits (2200) (Greedy + Constructive)
1003E.Tree Constructing (2100) (Tree + Constructive)
22E.Scheme (2300) (Graph + Constructive)
1558C.Bottom-Tier Reversals (2000) ( Constructive )
1582D.Vupsen, Pupsen and 0 (1600) ( Constructive )
490E.Restoring Increasing Sequence (2000) ( Constructive + Greedy)
1349B.Orac and Medians (2000) (Constructive + Thinking + Observation)
1187C.Vasya And Array(1800) (Constructive + Line Sweep)
238B.Boring Partition (1800) (Constructive + Greedy)
773C.Prairie Partition (2200) (Greedy + Constructive)
734F. Anton and School(2500) (Thinking + Constructive + Math)
1618E. Singers' Tour (1700) (MAth + Constructive)
323B. Tournament-graph (2200) (Constructive)
1166D.Cute Sequences (2200) (Greedy + Math + Constructive)
226D.The table (2100) (Constructive + Thinking ) (Thumb)
894C.Marco and GCD Sequence (1900) (Constructive)
878B.Teams Formation (2300) ( Thinking + Constructive)
1419E.Decryption (2100) (Math + Constructive)
1158C.Permutation recovery (2100) (Graph + Constructive)
1231E.Middle-Out (2200) (Greedy + Constructive)
1305E.Kuroni and the Score Distribution (2200) (Constructive)

Constructive : String less than with prefix

946E.Largest Beautiful Number (2200) (Constructive + Greedy)

Brute Force

1185F. Two Pizzas (2100) (Brute Force + Bit )
910B. Door Frames (1600) （ DFS ）
1500A. Going Home (1800) （Brute Force）
1217C. The Number Of Good Substrings (1700) (Brute Force )
962D. Merge Equals (1600) (Implementation)
988E. Divisibility by 25 (2100) ( Brute Force)
27E.Number With The Given Amount Of Divisors (2000) (DFS)
58C. Trees (1800) (Implentation)
1095D.Circular Dance (1600) (Implementation)
1244C.The Football Season (2000) (Math + Brute Force)
903E.Swapping Characters (2200) (Brute Force + Observation)
1311D. Three Integers (2000) ( Brute Force + 打表 )
992D.Nastya and a Game (2100) (Math + Brute Force)

Meet In Middle

1257F.Make Them Similar(2400) (Meet In Middle + Hash)

Time Complexity

1183F. Topforces Strikes Back (hard version) (2100) ( Brute Force + Time + Math )
466B. Wonder Room (2000) (Brute Force + Time Complexity)
1593D2.Half of Same (1900) (Time + Thinking)
1582F2.Korney Korneevich and XOR (hard version) (2400) ( Thinking )
1637E.Best Pair (Brute Force + Time)
1580C.Train Maintenance (2200) (Thinking + Brute Force)
1654E. Arithmetic Operations (2300) (Brute Force + Time Complexity)

优雅暴力1 : 启发式合并

965E.Short Code (2200) (Trie + Greedy + 启发式合并)
600E. Lomsat gelral (2300) (启发合并)
1380E. Merging Towers (2300) (启发式合并)

优雅暴力2 : 分块 (Square Root Decomposition)

785E.Anton and Permutation (2200) (分块 + 逆序对)

枚举 (暴力)

1108E1. Array and Segments (Easy version) (1800) (Brute Force)
1359D. Yet Another Yet Another Task (2000) (Brute Force )
1092C.Prefixes and Suffixes (1700) (Brute Force)

思维/Thinking/Observation

540E.Infinite Inversions (2100) (无限逆序对+ Fenwick Tree + Thinking)
1208D. Restore Permutation (1900) (Constructive + Thinking + Fenwick Tree)
977D. Divide by three, multiply by two (1400) (Sort + Greedy)
1355C. Count Triangles (1800) (Binary Search + Sliding Window)
1334C. Circle of Monsters (1600) (思维 + Brute Force)
1519D. Maximum Sum of Products (1600) (Observation)
176B. Word Cut (1700) (DP + Observation)
1156B. Ugly Pair (1800) (Greedy)
1468H. K and Medians (2200) (Greedy + Reverse Thinking)
5E. Bindian Signalizing (2400) (Stack + Thinking + Observation)
988D. Points and Powers of Two (1800) (Observation + Thinking + Brute Force)
1536D. Omkar and Medians (2000) ( Thinking + Observation)
222A. Shooshuns and Sequence (1200) (Observation + Thinking)
1151B.Dima and a Bad XOR (1600) (Thinking + Observation)
558C. Amr and Chemistry (1900) (Thinking + Time Complexity)
1542C. Strange Function (1600) (Thinking + Math)
1542B. Plus and Multiply (1500) (Thinking + Math)
1025C. Plasticine zebra (1600) (Observation )
899D.Shovel Sale (1800) (Math + Thinking)
1555D.Say No to Palindromes (1600) (Observation + Brute Force + Prefix Sum)
59D.Team Arrangement (2000) (Implementation + Greedy + Thinking)
1438D.Powerful Ksenia (2200) (Thinking)
1567F.One-Four Overload (2700) (Thinking + Observation + Constructice)
1593G.Changing Brackets (2200) (Obsetvation)
1550C.Manhattan Subarrays) (1700) (Observation + Brute Force)

Thinking : Low High Bound

1005E2.Median on Segments (General Case Edition) (2400) ( Bound + Prefix )

Thinking : MAX * 2 <= SUM

1030E.Vasya and Good Sequences (2000) (Thinking + Brute Force + Bit)

Thinking : Transfer

675C.Money Transfers (2100) (Thinking + Prefix Sum + Transfer)
622E.Ants in Leaves (2200) (Tree + Thinking + Greedy)

Thinking : Swap

1268C.K Integers (2300) (Thinking)

Thinking : Sort Array Connect Component

1553E. Permutation Shift (2100) (Thinking + Observation)

Reverse Thinking

863D. Yet Another Array Queries Problem (1800) (Reverse + Thinking)

Bit

1592E.Bored Bakry (2400) (Two Pointer + Bit + Prefix + Thinking)

逆数对

987E. Petr and Permutations (1800) (思维 + 逆数对)
911D. Inversion Counting (1800) (逆数对)
540EInfinite Inversions (2100) (无限逆序对+ Fenwick Tree + Thinking )

Game

1363C. Game On Tree (1600) ( Game + Greedy)
78C. Beaver Game (2000) (Game)
1527B1. Palindrome Game (easy version) (1200) (Game)
1527B2. Palindrome Game (hard version) (1900) (Game)
55C. Pie or die (1900) (Game)

Nim Game

15C. Industrial Nim (2000) ( Nim Game + Bit + Xor )

MinMax

39E. What Has Dirichlet Got to Do with That?(2000) (DP + Game + Optimization + MinMax)

Chessboard

1196E. Connected Component on a Chessboard (1800) (Chessboard + Constructive + Greedy)

差分

1108E2. Array and Segments (Hard version) (2100) (差分 + DP + Prefix)
174C. Range Increments(1800) （差分 + Constructive）
1443D. Extreme Subtraction (1800) (差分)
1110E.Magic Stones (2200) ( 差分)

二维差分

341D. Iahub and Xors(2500) (二维差分+2D Fenwick)

Math

32C. Flea (1700) ( Math )
1151C.Problem for Nazar (1800) (Math)
597A.Divisibility (1600) (Math)
255D.Mr. Bender and Square (1800) (Binary Search + Math)

Math : Equation

933B.A Determined Cleanup (2000) (Math + Constructive) (Thumb)
1004D.Sonya and Matrix (2300) (Thinking + Math Equation + Constructive)

Math : Mod

354C.Vasya and Beautiful Arrays (2100) (Thinking + Math Mod + 打表)

Math : Calculation

1216E2. Numerical Sequence (hard version) (2200) (Binary Search + Math)

Math : GCD / LCM

1154G. Minimum Possible LCM (2200) (Brute Force, LCM)
510D.Fox And Jumping (1900) (GCD + DP) （Thumb）
1146D.1146D (2100) (Math + GCD)

Math : 进制

552C.Vanya and Scales (1900) (进制)

Math ： n / 1 n / 2 n / 3 ... 除法分块

1603C. Extreme Extension (2300) (DP + Thinking + Math)
830C.Bamboo Partition (2300) (除法分块 + Math)

Number Theory

584D. Dima and Lisa (1800) （Math : 1个偶数可以拆两个素数 ）
1512G. Short Task (1700) （Brute Force + 打表）
1359E.Modular Stability (2000) (Thinking + Number Theory + Combination)
45G. Prime Problem (2200) (Number Theory + Constructive)
1029D.Concatenated Multiples (1900) (Hash + Mod)
1537D. Deleting Divisors (1700) (Game + Number Theory)
1285C. Fadi and LCM (1400) (Math)

费马小定理

919E. Congruence Equation (2100) (费马小定理)

CRT & EXCRT

1500B. Two chandeliers (2200) (CRT and EXCRT)

Exponentional with Mod

615D.Multipliers (2000) (Combination + Math)

PHI Function (GCD)

1575G.GCD Festival (2200) (GCD + PHI)

线性基

1101G.(Zero XOR Subset)-less (2300) (线性基)
845G.Shortest Path Problem? (2300) (线性基 + Graph + Thinking + Constructive)

Optimize 打表

222C. Reducing Fractions (1800) (超级打表) （Thump）
546D.Soldier and Number Game (1700) (打表 + Prefix Sum)

Fib Number

446C.DZY Loves Fibonacci Numbers (2400) (Segment Tree push down + Fib Number Property)

欧拉定理

1295D. ame GCDs (1800) (GCD + Euler)

Geometry

31D.Chocolate (2000) (Brute Force + Implementation + Geometry)

Combination

1185G2. Playlist for Polycarp (Hard version) (2600) (DP + Combination )
1516E. Baby Ehab Plays with Permutations (2500) (超难 Combination + DP + 容斥 + Permutation)
1515E. Phoenix and Computers (2200) (DP + Combination)
1513E. Cost Equilibrium (2300) （Observation + Combination）
57C. Array (1900) (Combination) (Thumb)
52B.Right Triangles (1600) (Combination)
224E.Partial Sums (1900) (Combination)
1536E. Omkar and Forest (2300) (Combination + Multiple BFS)
374B. Inna and Nine (1500) (Observation + Combination)
1550D. Excellent Arrays (2300) (Combination) (Thumb)
900D.Unusual Sequences (2000) (Combination + Math)
1557C.Moamen and XOR (1700) (Combination)
486D.Valid Sets (2100) (Tree + Combination)
336D.Vasily the Bear and Beautiful Strings (2100) (Combiniation + Observation)
1228E.Another Filling the Grid (2300) (DP + Combination)
1167F.Scalar Queries (2300) (Combination)
895D.String Mark (2100) (Com + String prefix)

Lucas Combination

451E.Devu and Flowers (2300) (容斥 + Lucas 定理)

Geometric Progression

327C.Magic Five (1700) (Geometric Progression)

Combination : Push N balls into M boxs -> C(N+M-1,N) || C(N+M-1,M-1)

213B. Numbers (1900) (DP + Combination)
439E. Devu and Birthday Celebration (2100) (Combination)
571A. Lengthening Sticks (2100) (Combination + Ball in box)
893E. Counting Arrays (2000) (Combination)
403D.Beautiful Pairs of Numbers (2200) (DP + Combination)
1622D.Shuffle (2000) (Thinking + Combination)

Probability

626D. Jerry's Protest (1800) (Combination + Probability)

容斥

803F.Coprime Subsequences (2000) (DP + 容斥 + Number Theory)
839D.Winter is here (2200) (容斥 + Combination)
1093F.Vasya and Array (2400) ( DP + 容斥)
920G.List Of Integers (2200) ( 容斥)
559C.Gerald and Giant Chess (2200) (Combination + DP + 容斥 + Unique Path 升级)
1342E.Placing Rooks (2300) (Com + 容斥) (Thumb)

二维容斥

1245F.Daniel and Spring Cleaning (2300) (数位DP + 二维容斥)

鸽子原理

577B. Modulo Sum (1900) （鸽子原理 + DP）(对prefixsum 进行鸽子原理)
125D. Two progressions (2200) (Greedy + 鸽子)
333D. Characteristics of Rectangles (2100) (Binary Search + 鸽子)
618F. Double Knapsack (3000) (鸽子原理)

Induction

1095C.Powers Of Two (1400) (Induction)
1311E. Construct the Binary Tree (2200) (Constructive + Induction) (Thumb)

Graph

1196F. K-th Path (2200) (思维 + Shortest Path + Floy + Brute Force)
1133F1. Spanning Tree with Maximum Degree (1600) (Greedy + Graph)
1133F2. Spanning Tree with One Fixed Degree (1900) (Greedy + Graph + UF + Strongly Connect)
1472G. Moving to the Capital (2100) ( Graph + DP)
1334D. Minimum Euler Cycle (1800) (Graph + Greedy + Constructive + Math)
22C. System Administrator (1700) ( Constructive + Graph)
24A. Ring Road (1400) (Graph)
1439B.Graph Subset Problems (2600) (Graph)
117C. Cycle (2000) (Graph)
920E. Connected Components? (2100) (Graph)
999E.Reachability from the Capital (2000) (Graph)
196B. Infinite Maze (2000) (Graph + Thinking + Matrix)
1005F.Berland and the Shortest Paths (2100) ( Graph + BFS )
67A.Partial Teacher (1800) (Direct Graph + DP)
986C.AND Graph (2500) (Graph)
301B.Yaroslav and Time (2100) (Shortest Path + Thinking ) (Thumb)
1364D.Ehab's Last Corollary (2100) (Graph + DFS 最小环)
915D.Almost Acyclic Graph (2200) (Graph + Thinking)
1355F.Robots on a Grid (2200) (Graph + Thinking)

Graph Model :

274D.Lovely Matrix (2200) (Graph Model + Topo)

Graph With String

886D. Restoration of string(2000) ( Graph + Construtive + String )

Maximum Independent Set

1105E. Helping Hiasat (2200) ( Maximum Independent Set + DP )

三环/四环图

1468M. Similar Sets (2300) (Graph + 四环图)

Tarjan (Bridge)

160D.Edges in MST (2300) (Graph + MST + Tarjan)

Direct Tarjan (SCC)

894E.Ralph and Mushrooms(2100) (Tarjan Direct) |2021/01/30|

Direct Graph Cycle

1411C. Peaceful Rooks (1700) （Cycle Direct Graph）
1547G. How Many Paths? (2100) (Direct Graph Cycle + DP )
1217D. Coloring Edges (2100) (Direct - Graph + Thinking)

Bipartite Graph

1354E. Graph Coloring (2100) (DP + Bipartite Graph)
27D. Ring Road 2(2200) ( Bipartile Graph)
1537F. Figure Fixing (2200) (Graph + Bipartile)

无向图缩点

1220E.Tourism (2200) (无向图缩点 + Tree DP ) (Thumb)

Online Bipartite Check

813F. Bipartite Checking (2500) (Dynamic Connectivity + Online Bipartile checking)

Euler Path

788B.Weird journey (2100) (Euler Path + Thinking)

Shortest Path

416E. President's Path(2500) （Shortest Path + DP）
1486E. Paired Payment (2200) （Graph + SPFA）
1520G. To Go Or Not To Go? (2200) (Graph + Shortest Path )
1473E. Minimum Path (2400) (Shortest Path)
37E. Trial for Chief(2600) (Shortest Path + Thinking) (Thumb)
450D. Jzzhu and Cities (2000) (Shortest Path + Thinking) (Thumb)
545E.Paths and Trees (2000) (shortest path + thinking)
386D.Game with Points (2100) (Shortest Path)
1051F. The Shortest Statement (2400) (LCA + Shortest Path + Tree + Thinking )
59E.Shortest Path (2000) (Shortest Path)
1070A. Find a Number(2200) (Shortest Path)
543B. Destroying Roads (2100) (Shortes Path + Thinking) (Thumb)
369D. Valera and Fools (2200) (Thinking + Shortest Path + DP)
821D.Okabe and City (2200) (Graph Building + Shortest Path) (Thumb)
1650G.Counting Shortcuts (2100) (Shortest Path + DP)
1442C.Graph Transpositions (2400) (Thinking + Shortest Path)

0-1 BFS

1063B. Labyrinth (1800) (Thinking + 01-BFS )

Floy

33B String Problem (1800) (Shortest Path)

Shortest Cycle in Weight-1 graph

1205B. Shortest Cycle(1900) (Shortest Cycle in Weight1) (Thumb)

Min Cost Maximum Flow

237E. Build String (2000) （Minimum Cost Max Flow ）
316C1.Tidying Up (2200) (Maximum Flow Minimum Cost)

2-Sat

776D. The Door Problem (2000) (2 Sat)
1475F. Unusual Matrix (1900) (2 Sat)

Topo :

274D.Lovely Matrix (2200) (Graph Model + Topo)

UF

292D.Connected Components (1900) (UF + Graph + Thinking)
195E.Building Forest (2000) (UF + Tree) (Thumb)
1618G. Trader Problem (2200) (UF + Sort)

MST

125E. MST Company (2400) (MST + Thinking)
1095F.Make It Connected (1900) (MST + Greedy)
1242B. 0-1 MST (1900) (MST + Graph)
1108F. MST Unification (2100) (MST + Thinking)
1657E. Star MST (2200) (MST + DP + Combination)

Boruvka's algorithm

888G. Xor-MST (2300) (MST + Trie + Bit + Divide Conquer + Boruvka's algorithm)

Dynamic Connectivity

1140F.Extending Set of Points (2600) （Dynamic Connectivity）
813F. Bipartite Checking (2500) (Dynamic Connectivity + Online Bipartile checking)

SCC (Strong Connected Component)

118E. Bertown roads (2000) (Graph + Tarjan + SCC)

DFS/剪枝

448E. Divisor (2200) (DFS + 剪枝)

Tree

1528A. Parsa's Humongous Tree (1600) (Tree + DP)
61D. Eternal Victory (1800) (Tree)
1092E. Minimal Diameter Forest (Tree + Greedy)
960D.Full Binary Tree Queries (2100) (Math + Tree)
1551F.Equidistant Vertices (2200) (DP + Tree)
472D.Design Tutorial: Inverse the Problem(1900) (MST + Tree + Greedy)
963B.Destruction of a Tree (2000) (Tree)
700B.Connecting Universities (1800) (Greedy + Tree)
463E. Caisa and Tree (2100) (Tree )
859E. Desk Disorder (2100) (Combination + Tree + Graph )
980E.The Number Games (2200) (Tree + Sparse + Greedy) (Thumb)
1363E. Tree Shuffling (2000) (Tree + Greedy)
369C.Valera and Elections (1600) (Tree)
1632E1.Distance Tree (easy version) (2400) (Thinking + Tree + Brute Force)
1132G.Greedy Subsequences (2400) (Seg push + Tree + DP)

Tree Diameter

744F. Tree Destruction (2400) (Tree + Greedy )
734E. Anton and Tree (2100) (Tree)

Tree Euler Tour (Path Sum Query With Update)

1575I.Illusions of the Desert (2300) (Tree + LCS + Tree Euler + Tree Path Query)

Tree Re-range

337D.Book of Evil (2000) (Tree Re-Range)

树点分治

914E. Palindromes in a Tree (2400) (点分治)

Centroid Decomposition

342E.Xenia and Tree (2400) (Centroid Decomposition)

Binary Search Tree

675D.Tree Construction (1800) (Binary Search Tree + Observation)

TreeSet/TreeMap

926J.Segments (2100) (Tree Set + Merge Set )
45C. Dancing Lessons (1900) (TreeMap)

Fenwick Tree

1364C. Ehab and Prefix MEXs (1600) (Greedy + BIT)
1354D.Multiset (1900) (Fenwick Tree)
899F.Letters Removing (2100) (BinarySearch + Fenwick)
459D.Pashmak and Parmida's problem (1800) (Fenwick Tree)
1553F. Pairwise Modulo (2300) (Fenwick + Math + Thinking)
1579E2.Array Optimization by Deque (1700) (Fenwick)
703D.Mishka and Interesting sum (2100) (Fenwick + Thinking)
1616E.Lexicographically Small Enough(2200) (Fenwick)

Sparse Table

45B.School (2200) (DP + Sparse Table + Brute Force + Time)
466E. Information Graph (2100) (OffLine + Sparse Table + Tree)
359D. Pair of Numbers (2000) (Binary Search + Sparse Table)
475D.CGCDSSQ (2000) (GCD + Sparse Table)

LCA

1328E. Tree Queries (1900) （LCA + Sprase Table + Thinking）Thumb up!
609E.Minimum spanning tree for each edge (2100) (MST + Thinking + LCA Template)
519E.A and B and Lecture Rooms (2100) (Tree + LCA)
597C.Duff in the Army (2200) (LCA)
1304E.1-Trees and Queries (2000) ( LCA )
165D.Beard Graph (2100) (LCA + Fenwick)

Cartesian Tree

1220F.Gardener Alex (2700) (Cartesian Tree + Binary Search + Segment Tree + Tree)

Segment Tree

981E. Addition on Segments (2200) （Dp + Segment Tree + Divide Conquer）
911G. Mass Change Queries (2500) (Segment Tree Tag )
474F.Ant colony (2100) (Segment Tree + GCD + Binary Search)
756C.Nikita and stack (2200) (Thinking + Segment Tree)
1585E.Frequency Queries (2400) (Seg)

PushDown

877E. Danil and a Part-time Job (2000) (Tree + Segment Tree Push)
833B. The Bakery (2200) (DP + Seg push down)
446C.DZY Loves Fibonacci Numbers (2400) (Segment Tree push down + Fib Number Property)
1295E.Permutation Separation (2200) (Segment Tree pushDown + Thinking)
1326E.Bombs (2400) (Thinking + Seg push down)
1527E.Partition Game (2500) (DP + Thinking + Seg push down)
85D.Sum of Medians (2300) (Seg push + Thinking)
620E.New Year Tree (2100) (Seg Push + Tree + Bit)
817F.MEX Queries (2300) (Segment Update + rever a bit rangg + Cpp) (Thumb)

Lazy Segment Tree

960F.Pathwalks (2100) (DP + Lazy Segment Tree)

Segment Tree Set Range

1439C. Greedy Shopping (2600) (Segment Tree Range Update + Segment Tree Binay Search)
558E. A Simple Task (2300) (Segment Tree Range Update)
1136E.Nastya Hasn't Written a Legend (2200) (Segment SetTo + Math)
343D.Water Tree (2100) (Tree + Seg push)

Segment Tree Range Update

52C. Circular RMQ (2200) (Range Update Min Lazy Seg)
1555E.Boring Segments (2100) (Seg + Range Update)

Persistant Segment Tree

484E. Sign on Fence (2500) (Persistant Segment Tree + Segment Tree Merge Interval + Binary Search)
813E. Army Creation (2200) (Thinking + Persistant Tree)
1000F.One Occurrence (2400) (莫队，主席树)
786C.Till I Collapse (2400) (Persistant Tree)

Binary Search

1379C. Choosing flowers (2000) （Binary Search + Math）
1177B. Digits Sequence (Hard Edition) (1800) (Binary Search + Math)
448D. Multiplication Table (1800) (Binary Search )
1066D. Boxes Packing (1800) (Binary Search)
1538G. Gift Set (2100) (BinarySearch + Math)
1547F. Array Stabilization (GCD version) (2100) (Math + BinarySearch + Segment Tree + GCD )
808D. Array Division (1900) (Binary Search + Prefix Sum )
349C.Mafia(1600) (Binary Search + Thinking)
258C.Little Elephant and LCM (2000) ( Binary Search )

Binary Search in Convex Line

439D.Devu and his Brother (1700) (Binary Search + Convex Line)

Tenary Search

1355E. Restorer Distance (2100) (Tenery Search)
808E.Selling Souvenirs (2300) (Tenary Search)

String Algorithm

String Polynominal Hash / Rolling Hash

514C.Watto and Mechanism (2000) (String Polynomial Hash)
1056E.Check Transcription (2100) (Rolling Hash)

Z-Algorithm

126B. Password (1700) (KMP+ Z algorithm)
1537E2. Erase and Extend (Hard Version) (2200) (Suffix Structure + Z-algorithm)

KMP

1015F. Bracket Substring (2300) (DP + KMP)
1029A.Many Equal Substrings (1300) (KMP)
432D.Prefixes and Suffixes (2000) (KMP + DP)

Suffix Array (LCP)

123D. String (2300) (Suffix Array LCP + Stack)

Expression Tree

552E.Vanya and Brackets (2100) (Expression Tree + Observation)

莫队

1514D. Cut and Stick (2000) (Greedy + 莫队 + Update max)
86D. Powerful Array (2200) （莫队）
940F. Machine Learning (2600) （莫队修改）
617E. XOR and Favorite Number (2200) (莫队 + Prefix)

Bit

1174D.Ehab and the Expected XOR Problem (1900) (bit + Thinking + Prefix )
1513B. AND Sequences (1400) （Bit + Greedy + Combination）
1338B. Edge Weight Assignment (1800) （Greedy + Bit + Tree）
1234D. Distinct Characters Queriese (1600) (TreeSet)
276D. Little Girl and Maximum XOR (1700) (Bit + Greedy)

Divide Conquer

652D. Nested Segments (1800) （Sort + Divide Conquer + Thinking）
1156E. Special Segments of Permutation (2200) (Divide Conquer + Segment Tree) (Thumb)
888E. Maximum Subsequence (1800) （Divide Conquer + Meet in Middle ）
1520F2. Guess the K-th Zero (Hard version) (2200) (Binary Search+ Divide Conquer)
1400E. Clear the Multiset (2200) (Greedy + Divide Conquer) (Thumb)
1601C. Optimal Insertion (2300) (Divide Conquer)

CDQ

848C. Goodbye Souvenir(2600) (CDQ 分支)
1093E. Intersection of Permutations (2400) (CDP 分支二维)

Meet in Middle

912E.Prime Gift (2400) (Brute Force + Meet in Middle)

Divide Conquer : Merge

1567E.Non-Decreasing Dilemma (2200) (Segment Tree + Divide Conquer)

FFT

954I. Yet Another String Matching Problem (2200) (FFT)

Interactive

1520F1. Guess the K-th Zero (Easy version) (1600) (Binary Search)

Sort

45D. Event Dates (1900) (Sort)
1183G. Candy Box (hard version) (hard version) (2000) ( Sort + Greedy )
978G. Petya's Exams (1700) (Greedy + Sort)
73B. Need For Brake (2000) (Greedy + Sort)
1151D.Stas and the Queue at the Buffet (1600) (Sort + Greedy)
1547E. Air Conditioners (1500) (left/right dp + sort)
12D. Ball (2400) (Sort + Segment Tree)
1213D2.Equalizing by Division (hard version) (1600) (Sort)
754D.Fedor and coupons (2100) (Sort)

Two Heap

220C.Little Elephant and Shifts (2100) (Two Heap Moving + Thinking)

Interval Problem

1029C.Maximal Intersection (1600) (Left/Right DP + Interval Problem)
1285E. Delete a Segment (2300) (Interval Problem + TreeMap + BinarySearch + left/right DP + Segment Tree)
863E. Turn Off The TV (2000) (Interval Problem)
369E. Valera and Queries(2200) (offline + Fenwick + Thinking + Line)
1638E.Colorful Operations (2400) (Thinking + Interval Problem)
915E.Physical Education Lessons (2300) (Interval)

Line Sweep

689E.Mike and Geometry Problem (2000) (Combination + Lined Sweep) (Thumb)
1630C.Paint the Middle(2200) ( Thinking + Interval)

Two Pointer

190D. Non-Secret Cypher (1900) (Two Pointer + Segment Tree)
224B. Array (1500) (Two Pointer + Thinking)
1029F.Multicolored Markers (2000) (Two Pointer)
386C.Diverse Substrings (2000) (Two Pointer)
514D.R2D2 and Droid Army (2000) (Two Pointer + Segment Tree)
846F.Random Query (1800) (Two Pointer)
1244E.Minimizing Difference (2000) (Two Pointer + Greedy)
954G. Castle Defense (2000) (Binary Search + Two Pointer)
620D.Professor GukiZ and Two Arrays (2200) ( Two Pointer )
1322B.Present (2100) (Math + Bit + Two Pointer)
1632D.New Year Concert (2000) ( Two Pointer + Seg + GCD)

Trie

37C. Old Berland Language (1900) (Dfs + Trie)
1285D. Dr. Evil Underscores (1900) (Bit + Trie)
665E.Beautiful Subarrays (2100) (Trie + XOR + Array Implementation)

Trie Bitmask:

842D.Vitya and Strange Lesson (2000) (Trie + Bitmask + Thinking)
979D.Kuro and GCD and XOR and SUM (2200) (Trie)

Stack

224C. Bracket Sequence (1700) (Stack)
280B.Maximum Xor Secondary (1800) (Monotic Stack)
817D.Imbalanced Array (1900) (Stack) (Thumb)

LinkedList

899E.Segments Removal (2000) (UF + Double LinkedList)
920F.SUM and REPLACE (2000) (Double LinkedList + UF)
670E.Correct Bracket Sequence Editor (1700) (LinkedList)

十字链表

89C. Chip Play (2300) (DFS + 十字linkedlist)

Regular Bracket

1095E.Almost Regular Bracket Sequence (1900) (Implementation)

K-Skip (i+k)

571B. Minimization (2000) (DP + k skip)

特训

1270G.Subset with Zero Sum (2700) (Thinking + Graph + Sort + Math)

Flow

362E.Petya and Pipes (2300) (mcmf)
546E.Soldier and Traveling (2100) (flow + Graph Construct)

ACWing 专题

ACW 89. a ^ b (E） （快速幂）
ACW 92. 递归实现指数型枚举 (E） （枚举）
ACW 103. 电影 (E） （HashMap）
ACW 104. 货仓选址 (E） （中位数）
ACW 107. 超快速排序 (E） （逆序对 + 树状数组）
ACW 109. 天才ACM (H） （倍增 + 时间判断）
ACW 122. 糖果传递 (M） （思维 + 中位数）
ACW 147. 数据备份 (H） （思维 + 贪心 + 堆）
ACW 158. 项链 (E） （string 最小表示法）
ACW 201. 可见的点 (E） （欧拉函数模板）
ACW 212. 计数交换 (E） （组合）
ACW 214. Devu和鲜花 (M） （容斥 + 组合）
ACW 230. 排列计数 (E） （错排 + 组合）
ACW 244. 谜一样的牛 (E） （二分法 + BIT）
ACW 255. 第K小数 (M） （二分法 + 主席树）
ACW 256. 最大异或和 (M） （可持续Trie）
ACW 257. 关押罪犯 (M） （二分 + 二分图染色）
ACW 300. 任务安排1 (M） （DP + Thinking）
ACW 301. 任务安排2 (H） （DP + 斜率优化模板）
ACW 302. 任务安排3 (H） （DP + 非单调斜率优化模板）
ACW 310. 启示录 (M） （数位DP）
ACW 333. 最大子矩阵 (E） （DP + stack）
ACW 345. 牛站 (M） （倍增 + 最短路）
ACW 372. 棋盘覆盖 (M） （二分图最大匹配）
ACW 373. 車的放置 (E） （二分图最大匹配）

Leetcode

84. Largest Rectangle in Histogram (H） （Cartesian Tree）
2097. Valid Arrangement of Pairs (H） （Eulaer path + Eule Circuit）

Kickstart

2021 D3. Final Exam (TreeSet)
2021 D2. Cutting Interval (Line Sweep)

Some Article

1. https://blog.csdn.net/my_sunshine26/article/details/77385809 (组合数学:球问题)

专题练习

Geometry (训练集)

https://github.com/JunBinLiang/Geometry