LeetCode 100. Same Tree 判断两棵二叉树是否相等

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

方法一：使用递归（C++）

1 bool isSameTree(TreeNode* p, TreeNode* q) {
2         if(p==NULL&&q==NULL)
3             return true;
4         if((!p&&q)||(p&&!q)||(p->val!=q->val))
5             return false;
6         return isSameTree(p->left,q->left)&&isSameTree(p->right,q->right);
7     }