原创

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Sum Problem

Time Limit: 1000/500 MS (Java/Others) Memory Limit: 65536/32768 K (Java/Others)

Total Submission(s): 560410 Accepted Submission(s): 142045

Problem Description

Hey, welcome to HDOJ(Hangzhou Dianzi University Online Judge).

In this problem, your task is to calculate SUM(n) = 1 + 2 + 3 + ... + n.

 

Input

The input will consist of a series of integers n, one integer per line.

 

Output

For each case, output SUM(n) in one line, followed by a blank line. You may assume the result will be in the range of 32-bit signed integer.

 

Sample Input

1

100

 

Sample Output

1

 

5050

 

Author

DOOM III

 

　　

此题有个小坑，每一个输入输出案例之间都要有一个空行：

2

3

(空行)

100

5050

Accepted

1 import java.util.*; 2  3 public class HDOJ_1001 { 4  5     public static void main(String[] args) { 6         Scanner reader=new Scanner(System.in); 7         while(reader.hasNext()) { 8             long n=reader.nextInt(); 9             long sum=((1+n)*n)/2;10             System.out.println(sum);11             System.out.println();;12         }13     }14 15 }

12:04:33

2018-08-15