[LeetCode] 100. Same Tree

题目链接：传送门

Description

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

Solution

题意：

判断两棵树是否完全相同

思路：

递归，判根判左右

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