leetcode题记——Same Tree

原创于 2018-02-08 15:19:25 发布 · 137 阅读

0 ·

CC 4.0 BY-SA版权

java 同时被 2 个专栏收录

38 篇文章

订阅专栏

leetcode

38 篇文章

订阅专栏

本文介绍了一种用于检查两棵二叉树是否完全相同的算法。该算法通过递归比较两棵树的节点值及其子树来判断它们是否结构一致且节点值相同。文中还提供了具体的示例输入和预期输出。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

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

/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) { val = x; }
 * }
 */
class Solution {
    public boolean isSameTree(TreeNode p, TreeNode q) {
        if(p == null && q == null) {
            return true;
        } else if(p == null || q == null) {
            return false;
        }

        boolean isLeftSame = isSameTree(p.left, q.left);
        boolean isRightSame = isSameTree(p.right, q.right);

        return p.val==q.val && isLeftSame && isRightSame;
    }
}