Merge pull request #1519 from JakeVander/master

添加 0090.子集II.md Python3版本

problems/0090.子集II.md

@@ -261,6 +261,33 @@ class Solution:
             self.path.pop()
 ```
 
+### Python3 
+```python3
+class Solution:
+    def subsetsWithDup(self, nums: List[int]) -> List[List[int]]:
+        res = []
+        path = []
+        nums.sort() # 去重需要先对数组进行排序
+
+        def backtracking(nums, startIndex):
+            # 终止条件
+            res.append(path[:])
+            if startIndex == len(nums):
+                return
+            
+            # for循环
+            for i in range(startIndex, len(nums)):
+                # 数层去重
+                if i > startIndex and nums[i] == nums[i-1]: # 去重
+                    continue
+                path.append(nums[i])
+                backtracking(nums, i+1)
+                path.pop()
+        
+        backtracking(nums, 0)
+        return res
+```
+
 ### Go 
 
 ```Go