[LeetCode]题解（python）：100 Same Tree

题目来源

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https://leetcode.com/problems/same-tree/

Given two binary trees, write a function to check if they are equal or not.

Two binary trees are considered equal if they are structurally identical and the nodes have the same value.

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题意分析

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Input: twon binary tree

Output: equal?

Conditions:判断两个二叉树是不是相等。

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题目思路

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逐一遍历，看是否相等。

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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 isSameTree(self, p, q):
        """
        :type p: TreeNode
        :type q: TreeNode
        :rtype: bool
        """
        def dfs(p, q):
            if p == None and q != None:
                return False
            if p != None and q == None:
                return False
            if p == None and q == None:
                return True
            if p.val != q.val:
                return False
            return dfs(p.left, q.left) and dfs(p.right, q.right)
        
        return dfs(p,q)