
문제

내 풀이
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.StringTokenizer;
public class Main {
public static void main(String[] args) throws Exception {
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
StringBuilder sb = new StringBuilder();
StringTokenizer st = new StringTokenizer(br.readLine(), " ");
int num = Integer.parseInt(st.nextToken());
int answer = num * (num - 1);
sb.append(answer);
System.out.println(sb.toString());
}
}
느낀점
조합론 이런 문제만 나오면 짱 좋겠다!