LeetCode OJ

题目：

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.

解题思路：

递归求解。先判断根，然后递归判断左子树和右子树

代码

/**
 * Definition for binary tree
 * 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;
        }
        else if (p != NULL && q != NULL && p->val == q->val ){
            return isSameTree(p->left, q->left) && isSameTree(p->right, q->right);
        } else {
            return false;
        }
    }
};