[LeetCode]题解（python）：114 Flatten Binary Tree to Linked List

题目来源

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https://leetcode.com/problems/flatten-binary-tree-to-linked-list/

Given a binary tree, flatten it to a linked list in-place.

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题意分析

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Input: binary tree

Output: flattened tree

Conditions:将一个二叉树压平为一个flatten 树，也就是一条斜线

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题目思路

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先将左右子树压平，然后将左子树嵌入到本节点与右子树之间。

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AC代码（Python）

# 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.
        """
        if root == None:
            return
        self.flatten(root.left)
        self.flatten(root.right)
        p = root
        if p.left == None:
            return
        p = p.left
        while p.right:
            p = p.right
        p.right = root.right
        root.right = root.left
        root.left = None