0112.路径总和 python 113添加迭代法

0112.路径总和 python 113添加迭代法

problems/0112.路径总和.md

@@ -519,6 +519,30 @@ class solution:
         return result
 ```
 
+**迭代法，用第二个队列保存目前的总和与路径**
+```python
+class Solution:
+    def pathSum(self, root: Optional[TreeNode], targetSum: int) -> List[List[int]]:
+        if not root:
+            return []
+        que, temp = deque([root]), deque([(root.val, [root.val])])
+        result = []
+        while que:
+            for _ in range(len(que)):
+                node = que.popleft()
+                value, path = temp.popleft()
+                if (not node.left) and (not node.right):
+                    if value == targetSum:
+                        result.append(path)
+                if node.left:
+                    que.append(node.left)
+                    temp.append((node.left.val+value, path+[node.left.val]))
+                if node.right:
+                    que.append(node.right)
+                    temp.append((node.right.val+value, path+[node.right.val]))
+        return result
+```
+
 ## go
 
 112. 路径总和