BEAKJOON JAVA ALGORITHM #2921(도미노)

https://www.acmicpc.net/problem/2921

import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; public class a2921 { public static void main(String[] args) throws NumberFormatException, IOException { BufferedReader br=new BufferedReader(new InputStreamReader(System.in)); int num=Integer.parseInt(br.readLine()); int sum=0; for(int i=0; i<=num;i++){ for(int j=num;j>=i;j--){ sum+=(i+j); } } System.out.println(sum); } }