100. Same Tree

题目

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

题意

判断两棵树是否完全相同

分析

DFS递归实现

实现

/** * 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 && q && p->val == q->val) {            return isSameTree(p->left, q->left)                    && isSameTree(p->right, q->right);        } else if (!p && !q) return true;        return false;    }};