diff --git a/Basic_Of_Algorithm/src/Today_22_05_19/menuRenew.java b/Basic_Of_Algorithm/src/Today_22_05_19/menuRenew.java
new file mode 100644
index 0000000..20d1cf6
--- /dev/null
+++ b/Basic_Of_Algorithm/src/Today_22_05_19/menuRenew.java
@@ -0,0 +1,75 @@
+package Today_22_05_19;
+
+import java.util.HashMap;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+
+public class menuRenew {
+	
+	static HashMap<String,Integer> map = new HashMap<>();
+	static ArrayList<String> answerList = new ArrayList<>();
+	
+	public static void main(String[] args) {
+		
+		String [] orders = {"ABCFG", "AC", "CDE", "ACDE", "BCFG", "ACDEH"};
+		int [] course = {2,3,4};
+		
+		for(int i=0;i<orders.length;i++) {
+			char[]temp = orders[i].toCharArray();
+			Arrays.sort(temp);
+			orders[i] = String.valueOf(temp);
+		}
+		
+		
+		for(int count : course) {
+			for(String order : orders) {
+				
+				dfs(count,order,"");
+			}
+			
+			
+			if(!map.isEmpty()) {
+				ArrayList<Integer> maxValue = new ArrayList<>(map.values());
+				int max = Collections.max(maxValue);
+				if(max>1) {
+					for(String key : map.keySet()) {
+						if(map.get(key)==max) {
+							answerList.add(key);
+						}
+					}
+				}
+			}
+			
+			
+			map.clear();
+		}
+		
+		Collections.sort(answerList);
+		
+		String[]answer = new String[answerList.size()];
+		
+		for(int i=0;i<answer.length;i++) answer[i] = answerList.get(i);
+		
+		for(String str : answer)System.out.print('"'+str+'"'+",");
+		
+		
+	}
+	
+	
+	static void dfs(int count,String order,String now) {
+		
+		if(count==0) {
+			map.put(now, map.getOrDefault(now, 0)+1);
+			return;
+		}
+		
+		for(int i=0;i<order.length();i++) {
+			
+			dfs(count-1,order.substring(i+1),now+order.charAt(i));
+		}
+		
+		
+	}
+
+}
diff --git a/Basic_Of_Algorithm/src/Today_22_05_19/rankingSearching.java b/Basic_Of_Algorithm/src/Today_22_05_19/rankingSearching.java
new file mode 100644
index 0000000..f1bc15c
--- /dev/null
+++ b/Basic_Of_Algorithm/src/Today_22_05_19/rankingSearching.java
@@ -0,0 +1,82 @@
+package Today_22_05_19;
+
+import java.util.*;
+
+public class rankingSearching {
+
+	static HashMap<String,ArrayList<Integer>> map = new HashMap<>();
+	
+	
+	public static void main(String[] args) {
+		
+		String [] info = {"java backend junior pizza 150","python frontend senior chicken 210","python frontend senior chicken 150","cpp backend senior pizza 260","java backend junior chicken 80","python backend senior chicken 50"};
+		String [] query = {"java and backend and junior and pizza 100","python and frontend and senior and chicken 200","cpp and - and senior and pizza 250","- and backend and senior and - 150","- and - and - and chicken 100","- and - and - and - 150"};
+		int [] answer = new int[query.length];
+		
+		for(String str : info) {
+			String []temp = str.split(" ");
+			dfs(temp,"",0);	
+		}
+		
+		for(String key:map.keySet()) {
+			Collections.sort(map.get(key));
+		}
+		
+		for(int i =0;i<query.length;i++) {
+			
+			query[i] = query[i].replaceAll(" and ", "");
+			String[]temp = query[i].split(" ");
+			answer[i] = map.containsKey(temp[0]) ? binarySearch(temp[0],temp[1]) : 0;
+			
+		}
+		
+		
+		for(int i : answer)System.out.println(i);
+		
+		
+	
+	}
+	
+	static int binarySearch(String now,String infoScore) {
+		
+		ArrayList<Integer> list = map.get(now);
+		
+		int score = Integer.parseInt(infoScore);
+		
+		int start = 0, end = list.size()-1;
+		
+		while(start<=end) {
+			
+			int mid = (start+end)/2;
+			
+			if(list.get(mid)<score) start = mid+1;
+			else end = mid-1;
+			
+			
+		}
+		
+		return list.size()-start;
+		
+		
+		
+	}
+	
+	static void dfs(String[]temp,String now,int count) {
+		
+		if(count==4) {
+			if(!map.containsKey(now)) {
+				map.put(now, new ArrayList<Integer>());
+			}
+			map.get(now).add(Integer.parseInt(temp[4]));
+			return;
+		}
+		
+		dfs(temp,now+"-",count+1);
+		dfs(temp,now+temp[count],count+1);
+	
+		
+		
+		
+	}
+	
+}
diff --git a/Basic_Of_Algorithm/src/Today_22_05_19/soosick.java b/Basic_Of_Algorithm/src/Today_22_05_19/soosick.java
new file mode 100644
index 0000000..db211b1
--- /dev/null
+++ b/Basic_Of_Algorithm/src/Today_22_05_19/soosick.java
@@ -0,0 +1,85 @@
+package Today_22_05_19;
+
+import java.util.*;
+
+public class soosick {
+
+	static long answer = 0;
+	static ArrayList<Long> numList = new ArrayList<>();
+	static ArrayList<Character> opList = new ArrayList<>();
+	static char [] op = {'+','-','*'};
+	static boolean []visited = new boolean[3];
+	
+	public static void main(String[] args) {
+		
+		String expression = "100-200*300-500+20";
+		
+		String num = "";
+		for(int i=0;i<expression.length();i++) {
+			
+			char ch = expression.charAt(i);
+			
+			if(ch>='0' && ch <= '9') {
+				num += ch;
+			}else {
+				numList.add(Long.parseLong(num));
+				num="";
+				opList.add(ch);
+			}
+		}
+		
+		numList.add(Long.parseLong(num));
+		
+		dfs(new char[3],0);
+		
+		System.out.println(answer);
+	}
+	
+	static Long change(char ch , long a, long b) {
+		if(ch=='+') return a + b;
+		else if(ch=='*') return a * b;
+		else if(ch=='-') return a - b;
+		else return (long)0;
+	}
+	
+	static void dfs(char[]p,int count) {
+		
+		if(count==3) {
+			 ArrayList<Long> numArr = new ArrayList<>(numList);
+			 ArrayList<Character> opArr = new ArrayList<>(opList);
+			
+			 for(int i=0;i<p.length;i++) {
+				 for(int j=0;j<opArr.size();j++) {
+					 if(opArr.get(j)==p[i]) {
+						 long a = change(opArr.remove(j),numArr.remove(j),numArr.remove(j));
+						 numArr.add(j,a);
+						 j--;
+					 
+					 }
+				 }
+			 }
+			 
+			 answer = Math.max(answer, Math.abs(numArr.get(0)));
+			 
+			 return;
+			 
+			 
+		}
+		
+		
+		
+		
+		for(int i=0;i<3;i++) {
+			if(!visited[i]) {
+				visited[i] = true;
+				p[count] = op[i];
+				dfs(p,count+1);
+				visited[i] = false;
+			}
+			
+		}
+		
+		
+		
+	}
+}
diff --git a/Basic_Of_Algorithm/src/programmers_level_01/no_1.java b/Basic_Of_Algorithm/src/programmers_level_01/no_1.java
new file mode 100644
index 0000000..98b3f78
--- /dev/null
+++ b/Basic_Of_Algorithm/src/programmers_level_01/no_1.java
@@ -0,0 +1,69 @@
+package programmers_level_01;
+
+import java.util.HashMap;
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.Set;
+public class no_1 {
+	
+	public static void main(String[] args) {
+		
+		String[]id_list = {"muzi", "frodo", "apeach", "neo"};
+		String [] report = {"muzi frodo","apeach frodo","frodo neo","muzi neo","apeach muzi"};
+		int k = 2;
+		
+		//나를 신고한 사람 리스트를 뽑음
+		//그 사이즈가 2 이상이면
+		//나를 신고한 사람한테 +1
+		
+		int[]result = new int[id_list.length];
+		
+		HashMap<String,Set<String>> singoList = new HashMap<>();
+		//나를 신고한 사람 리스트
+		HashMap<String,Integer> myList = new HashMap<>();
+		//내가 받을 매일 횟수
+		
+		for(int i=0;i<id_list.length;i++) {
+			singoList.put(id_list[i], new HashSet<>());
+			myList.put(id_list[i], 0);
+		}
+		
+		for(int i=0;i<report.length;i++) {
+			String[]temp = report[i].split(" ");
+			
+			String attack = temp[0];
+			String taker = temp[1];	
+			singoList.get(taker).add(attack);
+		
+			
+		}
+		
+		System.out.println(singoList);
+		
+		for(String key : singoList.keySet()) {
+			
+			if(singoList.get(key).size()>=k) {
+				
+				System.out.println(singoList.get(key));
+				
+				for(String str : singoList.get(key)) {
+					
+					myList.put(str, myList.get(str)+1);
+					
+					
+				}
+			}
+			
+		}
+		
+		for(int i=0;i<id_list.length;i++) {
+			
+			result[i] = myList.get(id_list[i]);
+			
+		}
+		
+		
+		for(int i : result)System.out.println(i);
+	}
+
+}
diff --git a/Basic_Of_Algorithm/src/programmers_level_01/no_2.java b/Basic_Of_Algorithm/src/programmers_level_01/no_2.java
new file mode 100644
index 0000000..aaa028c
--- /dev/null
+++ b/Basic_Of_Algorithm/src/programmers_level_01/no_2.java
@@ -0,0 +1,30 @@
+package programmers_level_01;
+
+public class no_2 {
+
+	public static void main(String[] args) {
+		
+	String new_id = "...!@BaT#*..y.abcdefghijklm";
+	
+	new_id = new_id.toLowerCase();
+	new_id = new_id.replaceAll("[^a-z1-9-_.]", "");
+	new_id = new_id.replaceAll("[.]{2,}", ".");
+	new_id = new_id.replaceAll("^[.]|[x]$", "");
+	
+	if(new_id.isEmpty())new_id ="a";
+	
+	if(new_id.length()>15) {
+		new_id = new_id.substring(0,15);
+		new_id = new_id.replaceAll("[.]$", "");
+	}
+	
+	if(new_id.length()<3) {
+		while(new_id.length()<3) {
+			new_id += new_id.charAt(new_id.length()-1);
+		}
+	}
+	
+	System.out.println(new_id);
+	
+	}
+}
diff --git a/Basic_Of_Algorithm/src/programmers_level_01/no_3.java b/Basic_Of_Algorithm/src/programmers_level_01/no_3.java
new file mode 100644
index 0000000..3b15d80
--- /dev/null
+++ b/Basic_Of_Algorithm/src/programmers_level_01/no_3.java
@@ -0,0 +1,22 @@
+package programmers_level_01;
+
+public class no_3 {
+	
+	public static void main(String[] args) {
+		
+		String s = "one4seveneight";
+		int answer = 0;
+		
+		String [] alpha = {"zero","one","two","three","four","five","six","seven","eight","nine"};
+		
+		
+		for(int i=0;i<alpha.length;i++) s = s.replaceAll(alpha[i], String.valueOf(i));
+			
+		answer = Integer.valueOf(s);
+		
+		
+		System.out.println(answer);
+		
+	}
+
+}
diff --git a/Basic_Of_Algorithm/src/programmers_level_01/no_4.java b/Basic_Of_Algorithm/src/programmers_level_01/no_4.java
new file mode 100644
index 0000000..764ff2d
--- /dev/null
+++ b/Basic_Of_Algorithm/src/programmers_level_01/no_4.java
@@ -0,0 +1,54 @@
+package programmers_level_01;
+
+import java.util.Stack;
+
+public class no_4 {
+
+	public static void main(String[] args) {
+		
+		
+		int[][]board = {{0,0,0,0,0},{0,0,1,0,3},{0,2,5,0,1},{4,2,4,4,2},{3,5,1,3,1}};
+		
+		int [] moves = {1,5,3,5,1,2,1,4};
+		
+		int answer = 0;
+		
+		Stack<Integer> stack = new Stack<>();
+		
+		for(int i=0;i<moves.length;i++) {
+			
+			int move = moves[i]-1;
+			
+			
+			for(int i2 = 0; i2 <board.length;i2++) {
+				
+				if(board[i2][move]!=0) {
+					
+					if(stack.isEmpty()) {
+						stack.add(board[i2][move]);
+						board[i2][move]=0;
+						break;
+					}
+					else {
+						if(stack.peek()==board[i2][move]) {
+							stack.pop();
+							answer ++;
+							board[i2][move]=0;
+							break;
+						}
+					}
+					
+					
+				
+				}
+				
+				
+				
+			}
+			
+		}
+		
+		System.out.println(answer*2);
+		
+	}
+}
diff --git a/Basic_Of_Algorithm/src/programmers_level_01/no_5.java b/Basic_Of_Algorithm/src/programmers_level_01/no_5.java
new file mode 100644
index 0000000..f1d60b5
--- /dev/null
+++ b/Basic_Of_Algorithm/src/programmers_level_01/no_5.java
@@ -0,0 +1,45 @@
+package programmers_level_01;
+
+import java.util.*;
+
+public class no_5 {
+
+	public static void main(String[] args) {
+		
+		int n = 5;
+		int []stages = {2,1,2,6,2,4,3,3};
+		
+		int []answer = new int[n];
+		
+		double users = stages.length;
+		
+		List<double[]> fail_rate = new ArrayList<>();
+		
+		int cnt = 0;
+		
+		for(int i=1;i<=n;i++) {
+			for(int j=0;j<stages.length;j++) {
+				if(i==stages[j]) {
+					cnt++;
+				}
+			}
+			if(cnt==0) {
+				fail_rate.add(new double[] {i,0});
+				continue;
+				
+			}
+			fail_rate.add(new double[] {i,cnt/users});
+			users -= cnt;
+			cnt =0;
+		}
+		
+		fail_rate.sort((a,b)->Double.compare(b[1], a[1]));
+		
+		for(int i=0;i<fail_rate.size();i++) {
+			answer[i] = (int)fail_rate.get(i)[0];
+		}
+		
+		for(int i : answer)System.out.println(i);
+		
+	}
+}
diff --git a/Basic_Of_Algorithm/src/programmers_level_01/no_6.java b/Basic_Of_Algorithm/src/programmers_level_01/no_6.java
new file mode 100644
index 0000000..fb0fd40
--- /dev/null
+++ b/Basic_Of_Algorithm/src/programmers_level_01/no_6.java
@@ -0,0 +1,52 @@
+package programmers_level_01;
+
+public class no_6 {
+	
+	public static void main(String[] args) {
+		
+		int n = 5;
+		
+		int[]arr1 = {9,20,28,18,11};
+		int[]arr2 = {30,1,21,17,28};
+		
+		String[]answer = new String[arr1.length];
+		
+		for(int i=0;i<answer.length;i++) {
+			
+			String temp = "";
+			
+			int a = arr1[i];
+			int b = arr2[i];
+			
+			String str1 = Integer.toBinaryString(a);
+			String str2 = Integer.toBinaryString(b);
+			
+			if(str1.length()<n) {
+				while(str1.length()<n) {
+					str1 = "0"+str1;
+				}
+			}
+			if(str2.length()<n) {
+				while(str2.length()<n) {
+					str2 = "0"+str2;
+				}
+			}
+			
+			for(int j=0;j<str1.length();j++) {
+				boolean flag = false;
+				if(str1.charAt(j)=='1'||str2.charAt(j)=='1') {
+					temp += "#";
+					flag = true;
+					continue;
+				}
+				if(!flag) temp += " ";
+				
+			}
+			
+			System.out.println(temp);
+		}
+		
+		
+	}
+
+}
diff --git a/Basic_Of_Algorithm/src/programmers_level_01/no_7.java b/Basic_Of_Algorithm/src/programmers_level_01/no_7.java
new file mode 100644
index 0000000..8835fbf
--- /dev/null
+++ b/Basic_Of_Algorithm/src/programmers_level_01/no_7.java
@@ -0,0 +1,68 @@
+package programmers_level_01;
+
+public class no_7 {
+	
+	public static void main(String[] args) {
+		
+		
+		String dartResult = "1S2D*3T";
+		
+		int answer = 0;
+		
+		//숫자가 나오면 넣어주면 되겠네
+		
+		int[]temp = new int[3];
+		
+		int idx = -1;
+		
+		for(int i=0;i<dartResult.length();i++) {
+			
+			String str = ""+dartResult.charAt(i);
+			
+			if(str.equals("1")&&i<dartResult.length()-1) {
+				if(dartResult.charAt(i+1)=='0') {
+					str = "10";
+				}
+			}
+			
+			if(str.equals("0") && i!=0) {
+				if(dartResult.charAt(i-1)=='1') continue;
+			}
+			
+			
+			switch (str) {
+			case "S": temp[idx] =(int)Math.pow(temp[idx], 1);
+				
+				break;
+			case "D": temp[idx] =(int)Math.pow(temp[idx], 2);
+				
+				break;
+			case "T": temp[idx] =(int)Math.pow(temp[idx], 3);
+				
+				break;
+			case "*": if(idx!=0)  temp[idx-1] *= 2;
+			 		  temp[idx] *= 2;
+				break;
+			case "#":  temp[idx] *= -1;
+				
+				break;
+			
+			default: idx++;
+					 temp[idx] = Integer.valueOf(str);
+					 
+				break;
+			}
+			
+			
+			
+		}
+		
+		for(int i=0;i<3;i++) {
+			System.out.println(temp[i]);
+			answer += temp[i];
+		}
+		
+		System.out.println(answer);		
+	}
+
+}
diff --git a/Basic_Of_Algorithm/src/programmers_level_2/no_1.java b/Basic_Of_Algorithm/src/programmers_level_2/no_1.java
new file mode 100644
index 0000000..375b4a4
--- /dev/null
+++ b/Basic_Of_Algorithm/src/programmers_level_2/no_1.java
@@ -0,0 +1,53 @@
+package programmers_level_2;
+
+public class no_1 {
+	
+	public static void main(String[] args) {
+		
+		String s ="abcabcabcabcdededededede";	
+		
+		int answer = Integer.MAX_VALUE;
+		
+		for(int i=1;i<=s.length()/2;i++) {
+				
+			String now = "",next = "";
+			String result = "";
+			int hit = 1;
+			for(int j=0;j<=s.length()/i;j++) {
+				
+				int start = j * i;
+				int end = i * (j+1) > s.length() ? s.length() : i  * (j+1);
+				
+				now = next;
+				next = s.substring(start,end);
+				
+				if(now.equals(next)) {
+					hit++;
+				}else {
+					result += processHit(hit) + now;
+					hit = 1;
+				}
+				
+				
+				
+				
+			}
+			
+			result += processHit(hit) + next;
+			
+			System.out.println(result);
+			
+			answer = Math.min(answer, result.length());
+		}
+		
+		
+		System.out.println(answer);
+		
+		
+		
+	}
+	static String processHit(int hit) {
+		return hit > 1 ? String.valueOf(hit) : "";
+	}
+
+}
diff --git a/Basic_Of_Algorithm/src/programmers_level_2/no_2.java b/Basic_Of_Algorithm/src/programmers_level_2/no_2.java
new file mode 100644
index 0000000..67169a0
--- /dev/null
+++ b/Basic_Of_Algorithm/src/programmers_level_2/no_2.java
@@ -0,0 +1,54 @@
+package programmers_level_2;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+
+public class no_2 {
+	
+	public static void main(String[] args) {
+		
+		String [] record = {"Enter uid1234 Muzi", "Enter uid4567 Prodo","Leave uid1234","Enter uid1234 Prodo","Change uid4567 Ryan"};
+		
+		ArrayList<String> answerList = new ArrayList<>();
+		
+		HashMap<String,String> map = new HashMap<>();
+		
+		for(String str : record) {
+			
+			String[]temp = str.split(" ");
+			
+			String action = temp[0];
+			if(action.equals("Leave")) continue;
+			String id = temp[1];
+			String nick = temp[2];
+			
+			map.put(id, nick);
+			
+		}
+		for(String str : record) {
+			
+			String[]temp = str.split(" ");
+			
+			String action = temp[0];
+			if(action.equals("Change")) continue;
+			String id = temp[1];
+			String nick = map.get(id);
+			
+			String ans = nick+"님이 " + (action.equals("Enter") ? "들어왔습니다." : "나갔습니다.");
+			
+			answerList.add(ans);
+			
+			
+		}
+		
+		String[]answer = new String[answerList.size()];
+		
+		
+		for(int i=0;i<answerList.size();i++)answer[i] = answerList.get(i);
+		
+		
+		for(String s : answer)System.out.println(s);
+		
+	}
+
+}
diff --git a/Basic_Of_Algorithm/src/programmers_level_2/no_4.java b/Basic_Of_Algorithm/src/programmers_level_2/no_4.java
new file mode 100644
index 0000000..9ab9456
--- /dev/null
+++ b/Basic_Of_Algorithm/src/programmers_level_2/no_4.java
@@ -0,0 +1,71 @@
+package programmers_level_2;
+
+public class no_4 {
+	
+	static char[] member = {'A','C','F','J','M','N','R','T'};
+
+	static String[]datas;
+	static int answer = 0;
+	
+	public static void main(String[] args) {
+		
+		int n = 2;
+		
+		String[]data = {"N~F=0", "R~T>2"};
+		
+		
+		datas = data.clone();
+		
+		boolean[]visited = new boolean[member.length];
+		
+		dfs(visited,"");
+		
+		System.out.println(answer);
+		
+	}
+	static void dfs(boolean[]visited,String now) {
+		
+		if(now.length()==member.length) {
+			if(check(now)) answer++;
+			
+			return;
+		}
+		
+		
+		for(int i=0;i<visited.length;i++) {
+			
+			if(!visited[i]) {
+				visited[i] = true;
+				String newOne = now + member[i];
+				dfs(visited,newOne);
+				visited[i] = false;
+			}
+			
+			
+		}
+		
+	}
+	static boolean check(String now) {
+		
+		for(String data : datas) {
+			
+			int pos1 = now.indexOf(data.charAt(0));
+			int pos2 = now.indexOf(data.charAt(2));
+			char ch = data.charAt(3);
+			int idx = data.charAt(4)-'0';
+			
+			if(ch=='=') {
+				if(!(Math.abs(pos1-pos2)==idx+1)) return false;
+			}else if(ch=='>') {
+				if(!(Math.abs(pos1-pos2)>idx+1)) return false;
+			}else if(ch=='<') {
+				if(!(Math.abs(pos1-pos2)<idx+1)) return false;
+			}
+			
+		}
+		
+		
+		return true;
+	}
+	
+}
diff --git a/Basic_Of_Algorithm/src/programmers_level_2/no_5.java b/Basic_Of_Algorithm/src/programmers_level_2/no_5.java
new file mode 100644
index 0000000..bfca776
--- /dev/null
+++ b/Basic_Of_Algorithm/src/programmers_level_2/no_5.java
@@ -0,0 +1,84 @@
+package programmers_level_2;
+
+import java.util.HashMap;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Arrays;
+
+public class no_5 {
+
+	static HashMap<String,Integer> map = new HashMap<>();
+	static ArrayList<String> answerList = new ArrayList<>();
+	
+	public static void main(String[] args) {
+		
+		String[] orders = {"ABCFG", "AC", "CDE", "ACDE", "BCFG", "ACDEH"};
+		int [] course = {2,3,4};
+		
+		for(int i=0;i<orders.length;i++) {
+			
+			char[]arr = orders[i].toCharArray();
+			Arrays.sort(arr);
+			orders[i] = String.valueOf(arr);
+			
+			
+			
+		}
+		
+		
+		for(int c : course) {
+			for(String order : orders) {
+				
+				dfs(c,order,"");
+				
+				
+			}
+			
+			if(!map.isEmpty()) {
+				ArrayList<Integer> list = new ArrayList<>(map.values());
+				int max = Collections.max(list);
+				if(max>1) {
+					for(String key : map.keySet()) {
+						if(map.get(key)==max) {
+							answerList.add(key);
+						}
+					}
+					
+				}
+				
+				
+				
+			}
+			
+			
+			map.clear();
+		}
+		
+		String[]answer = new String[answerList.size()];
+		
+		Collections.sort(answerList);
+		
+		for(int i=0;i<answerList.size();i++) answer[i] = answerList.get(i);
+		
+		for(String str : answer)System.out.println(str);
+	}
+	
+	static void dfs(int count, String order,String now) {
+		
+		if(count==0) {
+			
+			map.put(now, map.getOrDefault(now, 0)+1);
+			
+			return;
+		}
+		
+		
+		for(int i=0;i<order.length();i++) {
+			
+			dfs(count-1,order.substring(i+1),now + order.charAt(i));
+			
+		}
+		
+		
+	}
+}
diff --git a/Basic_Of_Algorithm/src/programmers_level_2/no_7.java b/Basic_Of_Algorithm/src/programmers_level_2/no_7.java
new file mode 100644
index 0000000..5e50510
--- /dev/null
+++ b/Basic_Of_Algorithm/src/programmers_level_2/no_7.java
@@ -0,0 +1,54 @@
+package programmers_level_2;
+
+public class no_7 {
+
+	public static void main(String[] args) {
+		
+		String p = ")(";
+		
+		String answer = change(p);
+		
+		System.out.println(answer);
+		
+	}
+	
+	static String change(String w) {
+		
+		if(w.isEmpty()) return "";
+		
+		int l = 0, r = 0;
+		
+		int i;
+		
+		for(i=0;i<w.length();i++) {
+			
+			if(w.charAt(i)=='(') l++;
+			else r++;
+			
+			if(l==r) break;
+		}
+		
+		String u = w.substring(0,i+1);
+		String v = w.substring(i+1);
+		
+		if(isRight(u)) u += change(v);
+		else {
+			String str = "(" + change(v) + ")";
+			u = u.substring(1,u.length()-1);
+			u = u.replaceAll("\\(", ".");
+			u = u.replaceAll("\\)", "(");
+			u = u.replaceAll("\\.", ")");
+			str += u;
+			return str;
+		}
+		return u;
+	}
+	static boolean isRight(String u) {
+		
+		if(u.charAt(0)==')') return false;
+		
+		
+		return true;
+	}
+	
+}
diff --git a/Basic_Of_Algorithm/src/programmers_level_2/no_8.java b/Basic_Of_Algorithm/src/programmers_level_2/no_8.java
new file mode 100644
index 0000000..dfa0305
--- /dev/null
+++ b/Basic_Of_Algorithm/src/programmers_level_2/no_8.java
@@ -0,0 +1,87 @@
+package programmers_level_2;
+
+import java.util.ArrayList;
+
+public class no_8 {
+	
+	public static void main(String[] args) {
+		
+		
+		String str1 = "FRANCE";
+		String str2 = "french";
+		
+		str1 = str1.toLowerCase();
+		str2 = str2.toLowerCase();
+		
+		ArrayList<String> arr1 = new ArrayList<>();
+		ArrayList<String> arr2 = new ArrayList<>();
+		
+		
+		
+		for(int i=0;i<str1.length()-1;i++) {
+			
+			char first = str1.charAt(i);
+			char second = str1.charAt(i+1);
+			
+			if((first>='a'&&first<='z')&&(second>='a'&&second<='z')) {
+				arr1.add(""+first+second);
+			}
+		}
+
+		for(int i=0;i<str2.length()-1;i++) {
+			
+			char first = str2.charAt(i);
+			char second = str2.charAt(i+1);
+			
+			if((first>='a'&&first<='z')&&(second>='a'&&second<='z')) {
+				arr2.add(""+first+second);
+			}
+		}
+		double son = 0;
+		double mom = 0;
+		
+		mom = arr1.size() + arr2.size();
+		
+		System.out.println(mom);
+		
+		for(int i=0;i<arr1.size();i++) {
+			String a = arr1.get(i);
+			
+			for(int j=0;j<arr2.size();j++) {
+				String b = arr2.get(j);
+				if(a.equals(b)) {
+					son++;
+					arr2.remove(j);
+					break;
+				}
+			}
+			
+			
+		}
+		
+		mom -= son;
+		
+		
+		System.out.println(mom);
+		System.out.println(son);
+		
+		double answer = 0;
+		
+		if(son==0 && mom==0) answer = 1;
+		else if(son==0 && mom!=0) answer = 0;
+		else answer = son/mom;
+		
+		
+		answer *= 65536;
+		
+		int result = (int) answer;
+		
+		if(result==0) result = 65536;
+		
+		System.out.println(result);
+		
+		
+		
+	}
+
+}
diff --git a/Basic_Of_Algorithm/src/programmers_level_2/no_9.java b/Basic_Of_Algorithm/src/programmers_level_2/no_9.java
new file mode 100644
index 0000000..8f00dac
--- /dev/null
+++ b/Basic_Of_Algorithm/src/programmers_level_2/no_9.java
@@ -0,0 +1,97 @@
+package programmers_level_2;
+
+import java.util.ArrayList;
+
+public class no_9 {
+
+	
+	
+	
+	static ArrayList<Long> numArr = new ArrayList<>();
+	static ArrayList<Character> opArr = new ArrayList<>();
+	static char[]op = {'+','-','*'};
+	static long answer = Integer.MIN_VALUE;
+	static boolean[]visited = new boolean[3];
+	
+	public static void main(String[] args) {
+		
+	String expression = "100-200*300-500+20";
+	
+	change(expression);
+		
+	dfs(new char[3] ,0);
+		
+	System.out.println(answer);
+	
+	}
+	
+	static Long changeNum(char ch , long a, long b) {
+	
+		if(ch=='+') return a+b;
+		else if(ch=='*') return a*b;
+		else if(ch=='-') return a-b;
+		
+		return (long) 0;
+	}
+	
+	static void dfs(char[]p,int count) {
+		
+		if(count==3) {
+			
+			ArrayList<Long> numList = new ArrayList<>(numArr);
+			ArrayList<Character> opList = new ArrayList<>(opArr);
+			
+			for(int i=0;i<op.length;i++) {
+				for(int j=0;j<opList.size();j++) {
+					if(opList.get(j)==p[i]) {
+						long a = changeNum(opList.get(j),numList.remove(j),numList.remove(j));
+						opList.remove(j);
+						numList.add(j,a);
+						j--;						
+					}
+				}
+			}
+			
+			
+			answer = Math.max(answer, Math.abs(numList.get(0)));
+			return;
+			
+		}
+		
+		
+		for(int i=0;i<op.length;i++) {
+			if(!visited[i]) {
+				visited[i] = true;
+				p[count] = op[i];
+				dfs(p,count+1);				
+				visited[i] = false;
+			}
+			
+		}
+		
+	}
+	
+	
+	static void change(String expression) {
+		
+		String num = "";
+		
+		for(int i=0;i<expression.length();i++) {
+			
+			char ch = expression.charAt(i);
+			
+			if(ch>='0'&&ch<='9') {
+				num += ch;
+			}else {
+				numArr.add(Long.parseLong(num));
+				opArr.add(ch);
+				num = "";
+				
+			}
+			
+		}
+		
+		numArr.add(Long.parseLong(num));
+		
+	}
+}