ZZULIOJ 1006: 求等差数列的和，Java

1006: 求等差数列的和

import java.util.*;
public class Main {
    public static void main(String[] args) {
    Scanner cin = new Scanner(System.in);int a=cin.nextInt();int b=cin.nextInt();int c=cin.nextInt();int d=(b-a)/c+1;System.out.println((a+b)*d/2);}
}