leetcode 617. Merge Two Binary Trees | 617. 合并二叉树（Java）

题目

https://leetcode-cn.com/problems/merge-two-binary-trees/

题解

测试用例

输入：
[1,3,2,5]
[2,1,3,null,4,null,7]
[1]
[1,2]
[1,null,2,null,3,null,4]
[1,2,null,3,null,4,null,5]
答案：
[3,4,5,5,4,null,7]
[2,2]
[2,2,2,3,null,null,3,4,null,null,4,5]

思路

同时遍历左右两棵二叉树，把右边的树上的值加到左边来。

这样做有一个不严谨的地方，是改变了原有二叉树的值，而题目中要求返回一个 new tree。

public static TreeNode mergeTrees(TreeNode root1, TreeNode root2) {if (root1 != null && root2 != null) {root1.val = root1.val + root2.val; // already ensure both nodes are not nullif (root1.left != null && root2.left != null)mergeTrees(root1.left, root2.left);if (root1.right != null && root2.right != null)mergeTrees(root1.right, root2.right);if (root1.left == null)root1.left = root2.left;if (root1.right == null)root1.right = root2.right;} else if (root1 == null) {root1 = root2;}return root1;
}

leetcode 617. Merge Two Binary Trees | 617. 合并二叉树（Java）相关推荐

617.Merge Two Binary Trees(合并两棵树)
Given two binary trees and imagine that when you put one of them to cover the other, some nodes of t ...
LeetCode 617. Merge Two Binary Trees
题目: Given two binary trees and imagine that when you put one of them to cover the other, some nodes ...
[leetcode] 617. Merge Two Binary Trees
题目描述给定两棵树,要求合并它们,如果节点重合则新合并的树的节点为它们之和,否则不变. 思路简单递归,c语言怎么创建新节点忘记了,就直接写的. 代码 /*** Definition for a b ...
【Tree-easy】617. Merge Two Binary Trees 合并两个二叉树
1. 题目原址 https://leetcode.com/problems/merge-two-binary-trees/ 2. 题目描述 3. 题目大意给定两个二叉树,现在要求将这两个二叉树合并, ...
《LeetCode力扣练习》第617题合并二叉树 Java
<LeetCode力扣练习>第617题合并二叉树 Java 一.资源题目: 给你两棵二叉树: root1 和 root2 . 想象一下,当你将其中一棵覆盖到另一棵之上时,两棵树上的一些 ...
C#LeetCode刷题之#617-合并二叉树（Merge Two Binary Trees）
问题该文章的最新版本已迁移至个人博客[比特飞],单击链接 https://www.byteflying.com/archives/4096 访问. 给定两个二叉树,想象当你将它们中的一个覆盖到另一个 ...
17. Merge Two Binary Trees 融合二叉树
［抄题］: Given two binary trees and imagine that when you put one of them to cover the other, some node ...
3/100. Merge Two Binary Trees
将两个二叉树相同位置的数值相加,相加的方法一样,则使用递归法挨个相加即可. # Definition for a binary tree node. # class TreeNode: # def _ ...
leetcode 1768. Merge Strings Alternately（交替合并字符串）
把word1和word2中的字母交替地整合成一个字符串. 思路: 很简单,主要是看什么时候放word1, 什么时候放word2, 可用一个0,1决定,每次异或1. public String merg ...

leetcode 617. Merge Two Binary Trees | 617. 合并二叉树（Java）

题目

题解

测试用例

思路

leetcode 617. Merge Two Binary Trees | 617. 合并二叉树（Java）相关推荐

最新文章

热门文章