[leetcode] 100. Same Tree 解题报告

题目链接：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.

思路：同时遍历一遍树，发现任何一个节点不相等则两棵树不相等。写水题的感觉好爽


代码如下：

/**
* Definition for a binary tree node.
* struct TreeNode {
*     int val;
*     TreeNode *left;
*     TreeNode *right;
*     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
* };
*/
class Solution {
public:
bool isSameTree(TreeNode* p, TreeNode* q) {
if(p == NULL && q == NULL)  return true;
if((p == NULL) ^ (q == NULL))   return false;
if(p->val != q->val)    return false;
return isSameTree(p->left, q->left) && isSameTree(p->right, q->right);
}
};