Create binary_tree_upside_down.py

yingl · web-flow · commit 4ae3a68cf1f5 · 2019-02-19T22:09:53.000+08:00
diff --git a/binary_tree_upside_down.py b/binary_tree_upside_down.py
@@ -0,0 +1,26 @@
+"""
+Definition of TreeNode:
+class TreeNode:
+    def __init__(self, val):
+        self.val = val
+        self.left, self.right = None, None
+"""
+
+class Solution:
+    """
+    @param root: the root of binary tree
+    @return: new root
+    """
+    def upsideDownBinaryTree(self, root):
+        # write your code here
+        # 递归版本，非递归待版本TODO。
+        if (root == None) or (root.left == None):
+            return root
+        _root = self.upsideDownBinaryTree(root.left)
+        root.left.left = root.right
+        root.left.right = root
+        root.left = None
+        root.right = None
+        return _root
+
+# medium: https://www.lintcode.com/problem/binary-tree-upside-down
