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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);
    }
};