Flatten Binary Tree to Linked List

Author: anantkaushik

114-flatten-binary-tree-to-linked-list.py

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+"""
+Problem Link: https://leetcode.com/problems/flatten-binary-tree-to-linked-list/
+
+Given a binary tree, flatten it to a linked list in-place.
+
+For example, given the following tree:
+
+    1
+   / \
+  2   5
+ / \   \
+3   4   6
+The flattened tree should look like:
+
+1
+ \
+  2
+   \
+    3
+     \
+      4
+       \
+        5
+         \
+          6
+"""
+# Definition for a binary tree node.
+# class TreeNode(object):
+#     def __init__(self, x):
+#         self.val = x
+#         self.left = None
+#         self.right = None
+
+class Solution(object):
+    def flatten(self, root):
+        """
+        :type root: TreeNode
+        :rtype: void Do not return anything, modify root in-place instead.
+        """
+        node = root
+        while node:
+            if node.left:
+                nodeL = node.left
+                while nodeL.right:
+                    nodeL = nodeL.right
+                tmp, node.left = node.left, None
+                nodeL.right, node.right = node.right, tmp
+            node = node.right