1. 题目描述

problem link

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

2. 解题

判断两棵二叉树是否相等，直接用随便一种遍历方式把两棵二叉树一起遍历一遍就好，注意需要条件判断的地方。

3. 代码

bool isSameTree(struct TreeNode* p, struct TreeNode* q) {
    if (p == NULL && q == NULL) {
        return true;
    }
    if (p == NULL || q == NULL) {
        return false;
    }

    if (p->val == q->val) {
        return isSameTree(p->left, q->left) && isSameTree(p->right, q->right);
    }
    else {
        return false;
}