[백준] 2740 행렬 곱셈 - Implementation / Java

• 문제 링크

https://www.acmicpc.net/problem/2740

 

• 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));
        StringBuilder sb = new StringBuilder();

        int n = read(), m = read();
        int[][] a = new int[n][m];
        for (int i = 0; i < n; i++) for (int j = 0; j < m; j++) a[i][j] = read();

        m = read();
        int k = read();
        int[][] b = new int[m][k];
        for (int i = 0; i < m; i++) for (int j = 0; j < k; j++) b[i][j] = read();

        for (int i = 0; i < n; i++, sb.append("\n")) {
            for (int j = 0; j < k; j++) {
                int sum = 0;
                for (int l = 0; l < m; l++) sum += a[i][l] * b[l][j];
                sb.append(sum).append(" ");
            }
        }

        bw.write(sb.toString());
        bw.flush();
    }

    private static int read() throws IOException {
        int c, n = System.in.read() & 15;
        boolean flag = n == 13;

        if (flag) n = System.in.read() & 15;
        while ((c = System.in.read()) > 32) n = (n << 3) + (n << 1) + (c & 15);

        return flag ? ~n + 1 : n;
    }

}