蓝桥杯 试题 基础练习 BASIC-02 序列求和 Java

• 全部代码

import java.util.Scanner;

public class Main {
public static void main(String[] args) {
	Scanner scanner = new Scanner(System.in);
	long n = scanner.nextLong();
	long sum = (n * (n+1) / 2);
	scanner.close();
	System.out.println(sum);
  }
}