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

 

 判断两棵二叉树是否完全一样

 

C++（3ms）：

1 /** 2  * Definition for a binary tree node. 3  * struct TreeNode { 4  *     int val; 5  *     TreeNode *left; 6  *     TreeNode *right; 7  *     TreeNode(int x) : val(x), left(NULL), right(NULL) {} 8  * }; 9  */10 class Solution {11 public:12     bool isSameTree(TreeNode* p, TreeNode* q) {13         if (p == NULL || q == NULL)14             return p == q ;15         return p->val == q->val && isSameTree(p->left , q->left) && isSameTree(p->right , q->right) ;16     }17 };