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;
    }
};