482. Binary Tree Level Sum

Given a binary tree and an integer which is the depth of the target level.

Calculate the sum of the nodes in the target level.

Example

Example 1:

Input:

     1
/ \
2 3
/ \ / \
4 5 6 7
/ \
8 9
and depth=2
Output:5

Example 2:

Input:

     1
/ \
2 3
/ \ / \
4 5 6 7
/ \
8 9
and depth=3
Output:22
 
思路:递归法

注意:

  1. sum 定义为类成员变量

代码:

/**
* Definition of TreeNode:
* public class TreeNode {
* public int val;
* public TreeNode left, right;
* public TreeNode(int val) {
* this.val = val;
* this.left = this.right = null;
* }
* }
*/ public class Solution {
/**
* @param root: the root of the binary tree
* @param level: the depth of the target level
* @return: An integer
*/
int sum = 0;
public int levelSum(TreeNode root, int level) {
helper(root, 1, level);
return sum;
}
public void helper(TreeNode root, int depth, int level) {
if (root == null) {
return;
} if (depth == level) {
sum += root.val;
return;
} helper(root.left, depth + 1, level);
helper(root.right, depth + 1, level);
}
}

Lintcode482-Binary Tree Level Sum-Easy的更多相关文章

  1. 【Leetcode】【Easy】Binary Tree Level Order Traversal II

    Given a binary tree, return the bottom-up level order traversal of its nodes' values. (ie, from left ...

  2. [LeetCode#110, 112, 113]Balanced Binary Tree, Path Sum, Path Sum II

    Problem 1 [Balanced Binary Tree] Given a binary tree, determine if it is height-balanced. For this p ...

  3. Binary Tree Level Order Traversal,Binary Tree Level Order Traversal II

    Binary Tree Level Order Traversal Total Accepted: 79463 Total Submissions: 259292 Difficulty: Easy G ...

  4. LeetCode(32)-Binary Tree Level Order Traversal

    题目: LeetCode Premium Subscription Problems Pick One Mock Articles Discuss Book fengsehng 102. Binary ...

  5. LeetCode_107. Binary Tree Level Order Traversal II

    107. Binary Tree Level Order Traversal II Easy Given a binary tree, return the bottom-up level order ...

  6. LeetCode107 Binary Tree Level Order Traversal II

    Given a binary tree, return the bottom-up level order traversal of its nodes' values. (ie, from left ...

  7. 63. Binary Tree Level Order Traversal II

    Binary Tree Level Order Traversal II My Submissions QuestionEditorial Solution Total Accepted: 79742 ...

  8. [LeetCode] Binary Tree Level Order Traversal II 二叉树层序遍历之二

    Given a binary tree, return the bottom-up level order traversal of its nodes' values. (ie, from left ...

  9. [LeetCode] Binary Tree Level Order Traversal 二叉树层序遍历

    Given a binary tree, return the level order traversal of its nodes' values. (ie, from left to right, ...

  10. 【leetcode】Binary Tree Level Order Traversal I & II

    Given a binary tree, return the level order traversal of its nodes' values. (ie, from left to right, ...

随机推荐

  1. 五子棋棋盘布局 table和ul哪个好

    想要在页面布局以上棋盘,可以用ul li 布局,但却有明显的缺点: 1.两行两列:ul li 下面如果再放li 会出错,只能是放其他的,比如div. 或者放li *行*列: 但是这样有两个明显缺陷: ...

  2. juqery 给本身的class加上一个class 或也可以实现关注商品,取消关注商品

    $("#goods1").on("click",".ICON-fen-LOVE",function(){ var $this = $(thi ...

  3. C语言定义的操作mysql数据库的接口

    编写的环境:centos7系统下,对mysql的衍生mariadb进行数据库的操作,包含设置访问数据库的参数,查询数据库和增删改数据库的三个功能.对于查询数据库,我这里允许不返回查询结果,用于判断查询 ...

  4. linux中的cd

    cd命令 实例 hling@hling:~$ cd /home/hling/桌面/huanghling@hling:~/桌面/huang$ cd ..hling@hling:~/桌面$ cd ..hl ...

  5. easyui equals验证代码

    在使用easyui textbox进行相等验证时却没有效果,经查询原来官方代码中没有提供equals验证的方法,搜了一个加上去就OK了: // extend the 'equals' rule $.e ...

  6. 山东13年省赛 Aliceand Bob

    Problem F: Alice and Bob Description Alice and Bob like playing games very much.Today, they introduc ...

  7. java_Arrays.sort()方法

    这个方法位于util包里,可以传入任一类型数组,默认按照字典序升序排序 如果要按照降序排序,直接写一个循环来颠倒顺序就好了 源码如下 String[] name = {"1",&q ...

  8. CentOS7.6 安装Docker

    删除已安装的Docker # Uninstall installed docker sudo yum remove docker \ docker-client \ docker-client-lat ...

  9. 《Mysql 用户管理》

    一:数据库用户 ROOT 和 其他用户有什么区别么? -  Mysql root 和 linux root 不是一回事,数据库 root 只不过是初始化时候自己建立的一个用户而已,随时可以删除/修改. ...

  10. 使用hashlib进行文件校验

    import hashlib import os path = r'D:\CentOS 64 位' def file_md5(path): """ 文件校验 :param ...