HDOJ 2132 An easy problem

HDACM 2132

注意sum(i-1)+i*i*i时，(long)i*i*i

import java.util.Scanner;public class Main {    public static void main(String[] args) {        long sum[] = new long [100001];        for (int i = 1; i < sum.length; i++) {            if (i%3==0) {                sum[i] = sum[i-1]+(long)i*i*i;            }else{                sum[i] = sum[i-1]+(long)i;            }        }        Scanner sc = new Scanner(System.in);        while(sc.hasNext()){            int n = sc.nextInt();            if (n<0) {                break;            }            System.out.println(sum[n]);        }        sc.close();    }}