100. Same Tree

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

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

Example 1:

Input:     1         1
          / \       / \
         2   3     2   3

        [1,2,3],   [1,2,3]

Output: true

Example 2:

Input:     1         1
          /           \
         2             2

        [1,2],     [1,null,2]

Output: false

Example 3:

Input:     1         1
          / \       / \
         2   1     1   2

        [1,2,1],   [1,1,2]

Output: false

这一题主要是考查二叉树的前向遍历

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

class Solution:
    def isSameTree(self, p: TreeNode, q: TreeNode) -> bool:
        result1=[]
        result2=[]
        def pre_order(ptr,result):
            if ptr:
                result.append(ptr.val)
                
                pre_order(ptr.left,result)
                
                
                pre_order(ptr.right,result)
            else:
                result.append('None')
        pre_order(p,result1)
        pre_order(q,result2)
        if result1==result2:
            return True
        return False

发表至：leetcode

2019-02-23

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