same-tree——比较两个二叉树是否相同

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.

 

思路同比较二叉树是否对称，使用递归的方法

/**
 * 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;
        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);
    }
};