Leetcode 树 Same Tree

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Same Tree

 Total Accepted: 15922 Total
Submissions: 38418

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.

题意：判断给定的两棵二叉树是不是一样

思路：dfs递归

两棵树一样的条件是

1.它们的根节点一样

2.它们的左子树一样

3.它们的右子树一样

复杂度：时间O(n)，空间O(log n)

相关题目：Symmetric Tree

/**
* Definition for binary tree
* 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) return false;
return p->val == q->val && isSameTree(p->left, q->left) && isSameTree(p->right, q->right);
}
};