100. same tree
难度: Easy
刷题内容
原题连接
- https://leetcode.com/problems/same-tree/
-
内容描述
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
思路1 **- 时间复杂度: O(N)*- 空间复杂度: O(1)***
这道题直接从两颗树的根节点开始递归比较，如果不同就返回false，反之则true
/**
* 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 != nullptr && q != nullptr)
{
if(p ->val != q ->val)
return false;
return isSameTree(p ->left,q ->left) && isSameTree(p ->right,q ->right);
}
return p == q ? true : false;
}
};
