题:https://leetcode.com/problems/flatten-binary-tree-to-linked-list/description/
题目
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
思路
递归,把左树放在右树的位置,将右树放到,左树的末端。
code
# Definition for a binary tree node.
# class TreeNode:
# def __init__(self, x):
# self.val = x
# self.left = None
# self.right = None
class Solution:
def flatten(self, root):
"""
:type root: TreeNode
:rtype: void Do not return anything, modify root in-place instead.
"""
if root == None:
return None
leftnode = root.left
rightnode = root.right
root.left = None
self.flatten(leftnode)
self.flatten(rightnode)
root.right = leftnode;
cur = root
while cur.right != None:
cur = cur.right
cur.right = rightnode