Update 0047.全排列II.md

problems/0047.全排列II.md

@@ -208,28 +208,25 @@ class Solution {
 
 ```python
 class Solution:
-    def permuteUnique(self, nums: List[int]) -> List[List[int]]:
-        # res用来存放结果
-        if not nums: return []
-        res = []
-        used = [0] * len(nums)
-        def backtracking(nums, used, path):
-            # 终止条件
-            if len(path) == len(nums):
-                res.append(path.copy())
-                return
-            for i in range(len(nums)):
-                if not used[i]:
-                    if i>0 and nums[i] == nums[i-1] and not used[i-1]:
-                        continue
-                    used[i] = 1
-                    path.append(nums[i])
-                    backtracking(nums, used, path)
-                    path.pop()
-                    used[i] = 0
-        # 记得给nums排序
-        backtracking(sorted(nums),used,[])
-        return res
+    def permuteUnique(self, nums):
+        nums.sort()  # 排序
+        result = []
+        self.backtracking(nums, [], [False] * len(nums), result)
+        return result
+
+    def backtracking(self, nums, path, used, result):
+        if len(path) == len(nums):
+            result.append(path[:])
+            return
+        for i in range(len(nums)):
+            if (i > 0 and nums[i] == nums[i - 1] and not used[i - 1]) or used[i]:
+                continue
+            used[i] = True
+            path.append(nums[i])
+            self.backtracking(nums, path, used, result)
+            path.pop()
+            used[i] = False
+
 ```
 
 ### Go