LeetCode 100: Same Tree

原创于 2015-10-27 19:43:27 发布 · 257 阅读

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#leetcode #二叉树

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本文介绍了一种通过递归方法来判断两个二叉树是否结构相同且节点值相等的算法。

Same Tree

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.

解题思路

递归（recursion），代码如下：

/**
 * 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 == NULL && q == NULL) return true;
        if (p == NULL || q == NULL) return false;

        if (p->val != q->val) return false;

        return isSameTree(p->left, q->left) && isSameTree(p->right, q->right);
    }
};