[Java] 백준 1292번 [쉽게 푸는 문제] 자바

문제: https://www.acmicpc.net/problem/1292

import java.util.ArrayList;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        ArrayList<Integer> list = new ArrayList<Integer>();

        int a = sc.nextInt();
        int b = sc.nextInt();
        int sum=0;

        for(int i=0; i<1000; i++) {
            for(int j=0; j<=i; j++) {
                list.add(i + 1); 
            }
        }

        for(int i=a-1; i<=b-1; i++) {
            sum += list.get(i);
        }

        System.out.println(sum);
    }
}