[백준] 16561 3의 배수 - Brute Force / Java

• 문제 링크

16561번: 3의 배수

 

• 풀이 코드

import java.io.BufferedWriter;
import java.io.IOException;
import java.io.OutputStreamWriter;

public class Main {

    public static void main(String[] args) throws IOException {
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));

        int n = read(), div = n / 3, cnt = 0;
        for (int i = 1; i < div; i++)
            for (int sub = i * 3, j = 1; j < div; j++)
                if (n - (sub + j * 3) >= 3) cnt++;

        bw.write(String.valueOf(cnt));
        bw.flush();
    }

    private static int read() throws IOException {
        int c, n = System.in.read() & 15;
        while ((c = System.in.read()) > 32) n = (n << 3) + (n << 1) + (c & 15);

        return n;
    }

}