LeetCode（100） Same Tree

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.

分析

判断两个二叉树是否相同。

采用递归的思想，当节点关键字以及左右子树均相同时，此两颗二叉树才相同；

AC代码

/**
 * 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) {
        //如果两个二叉树均为空，则返回true
        if (!p && !q)
        {
            return true;
        }
        //如果两者其一为空树，则返回false
        else if (!p || !q)
        {
            return false;
        }
        else{
            if (p->val != q->val)
                return false;
            else
                return isSameTree(p->left, q->left) && isSameTree(p->right, q->right);
        }
    }
};