From ab7e400850a0618aa9e6e48345cf01c34eccdc3f Mon Sep 17 00:00:00 2001
From: shining-ai <tderkkwii+social@gmail.com>
Date: Tue, 16 Apr 2024 17:59:59 +0000
Subject: [PATCH] =?UTF-8?q?=E3=80=90Arai60=E3=80=9152=E5=95=8F=E7=9B=AE=20?=
 =?UTF-8?q?39.=20Combination=20Sum?=
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---
 .../52_39_Combination Sum/level_1.py            | 17 +++++++++++++++++
 .../52_39_Combination Sum/level_2.py            | 17 +++++++++++++++++
 .../52_39_Combination Sum/level_3.py            | 17 +++++++++++++++++
 3 files changed, 51 insertions(+)
 create mode 100644 arai60/50-53_Greedy_Backtracking/52_39_Combination Sum/level_1.py
 create mode 100644 arai60/50-53_Greedy_Backtracking/52_39_Combination Sum/level_2.py
 create mode 100644 arai60/50-53_Greedy_Backtracking/52_39_Combination Sum/level_3.py

diff --git a/arai60/50-53_Greedy_Backtracking/52_39_Combination Sum/level_1.py b/arai60/50-53_Greedy_Backtracking/52_39_Combination Sum/level_1.py
new file mode 100644
index 0000000..1f0e34c
--- /dev/null
+++ b/arai60/50-53_Greedy_Backtracking/52_39_Combination Sum/level_1.py	
@@ -0,0 +1,17 @@
+# Backtracking
+class Solution:
+    def combinationSum(self, candidates: List[int], target: int) -> List[List[int]]:
+        def make_combination(remain, current, begin):
+            if remain == 0:
+                combinations.append(current[:])
+                return
+            if remain < 0:
+                return
+            for i in range(begin, len(candidates)):
+                current.append(candidates[i])
+                make_combination(remain - candidates[i], current, i)
+                current.pop()
+
+        combinations = []
+        make_combination(target, [], 0)
+        return combinations
diff --git a/arai60/50-53_Greedy_Backtracking/52_39_Combination Sum/level_2.py b/arai60/50-53_Greedy_Backtracking/52_39_Combination Sum/level_2.py
new file mode 100644
index 0000000..8b6de1b
--- /dev/null
+++ b/arai60/50-53_Greedy_Backtracking/52_39_Combination Sum/level_2.py	
@@ -0,0 +1,17 @@
+# Backtracking
+# 再帰が深いので、stackで書き直した
+class Solution:
+    def combinationSum(
+        self, candidates: List[int], target: int) -> List[List[int]]:
+        stack = [(target, [], 0)]
+        combinations = []
+        while stack:
+            before_remain, before_combination, begin = stack.pop()
+            for i in range(begin, len(candidates)):
+                remain = before_remain - candidates[i]
+                combination = before_combination + [candidates[i]]
+                if remain == 0:
+                    combinations.append(combination)
+                elif 0 < remain:
+                    stack.append((remain, combination, i))
+        return combinations
diff --git a/arai60/50-53_Greedy_Backtracking/52_39_Combination Sum/level_3.py b/arai60/50-53_Greedy_Backtracking/52_39_Combination Sum/level_3.py
new file mode 100644
index 0000000..f141169
--- /dev/null
+++ b/arai60/50-53_Greedy_Backtracking/52_39_Combination Sum/level_3.py	
@@ -0,0 +1,17 @@
+sys.setrecursionlimit(2000)
+class Solution:
+    def combinationSum(self, candidates: List[int], target: int) -> List[List[int]]:
+        def make_combinations(remain, combination, begin):
+            if remain < 0:
+                return
+            if remain == 0:
+                combinations.append(combination[:])
+                return
+            for i in range(begin, len(candidates)):
+                combination.append(candidates[i])
+                make_combinations(remain - candidates[i], combination, i)
+                combination.pop()
+
+        combinations = []
+        make_combinations(target, [], 0)
+        return combinations