【LeetCode】872. Leaf-Similar Trees 解题报告（Python）

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【LeetCode】872. Leaf-Similar Trees 解题报告（Python）

标签（空格分隔）： LeetCode

作者： 负雪明烛
id： fuxuemingzhu
个人博客： http://fuxuemingzhu.me/

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题目地址：https://leetcode.com/problems/leaf-similar-trees/description/

题目描述：

Consider all the leaves of a binary tree. From left to right order, the values of those leaves form a leaf value sequence.

For example, in the given tree above, the leaf value sequence is (6, 7, 4, 9, 8).

Two binary trees are considered leaf-similar if their leaf value sequence is the same.

Return true if and only if the two given trees with head nodes root1 and root2 are leaf-similar.

Note:

• Both of the given trees will have between 1 and 100 nodes.

题目大意

判断两棵二叉树的叶子节点从左到右的排列是否相同。

解题方法

一棵树从左到右的序列应该使用中序遍历，当中序遍历时，如果节点是叶子节点则放入序列之中。

所以判断两棵树的序列是否相等即可。

代码如下：

# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None

class Solution:
    def leafSimilar(self, root1, root2):
        """
        :type root1: TreeNode
        :type root2: TreeNode
        :rtype: bool
        """
        leaves1 = []
        leaves2 = []
        self.inOrder(root1, leaves1)
        self.inOrder(root2, leaves2)
        return leaves1 == leaves2

    def inOrder(self, root, leaves):
        if not root:
            return
        self.inOrder(root.left, leaves)
        if not root.left and not root.right:
            leaves.append(root.val)
        self.inOrder(root.right, leaves)

日期

2018 年 8 月 16 日 ———— 一个月不写题，竟然啥都不会了。。加油！