Update 0078.子集.md

problems/0078.子集.md

@@ -206,28 +206,20 @@ class Solution {
 ## Python 
 ```python
 class Solution:
-    def __init__(self):
-        self.path: List[int] = []
-        self.paths: List[List[int]] = []
+    def subsets(self, nums):
+        result = []
+        path = []
+        self.backtracking(nums, 0, path, result)
+        return result
 
-    def subsets(self, nums: List[int]) -> List[List[int]]:
-        self.paths.clear()
-        self.path.clear()
-        self.backtracking(nums, 0)
-        return self.paths
-
-    def backtracking(self, nums: List[int], start_index: int) -> None:
-        # 收集子集，要先于终止判断
-        self.paths.append(self.path[:])
-        # Base Case
-        if start_index == len(nums):
-            return
-
-        # 单层递归逻辑
-        for i in range(start_index, len(nums)):
-            self.path.append(nums[i])
-            self.backtracking(nums, i+1)
-            self.path.pop()     # 回溯
+    def backtracking(self, nums, startIndex, path, result):
+        result.append(path[:])  # 收集子集，要放在终止添加的上面，否则会漏掉自己
+        # if startIndex >= len(nums):  # 终止条件可以不加
+        #     return
+        for i in range(startIndex, len(nums)):
+            path.append(nums[i])
+            self.backtracking(nums, i + 1, path, result)
+            path.pop()
 ```
 
 ## Go