combination-sum solution(py)

Author: hi-rachel

combination-sum/hi-rachel.py

@@ -0,0 +1,20 @@
+# DFS + 백트래킹
+# 중복 조합 문제
+# O(2^t) time, O(재귀 깊이 (t) + 결과 조합의 수 (len(result))) space
+
+class Solution:
+    def combinationSum(self, candidates: List[int], target: int) -> List[List[int]]:
+        nums, result = [], []
+        def dfs(start, total):
+            if total > target:
+                return
+            if total == target:
+                result.append(nums[:])
+            for i in range(start, len(candidates)):
+                num = candidates[i]
+                nums.append(num)
+                dfs(i, total + num)
+                nums.pop()
+
+        dfs(0, 0)
+        return result