[백준] 2740 행렬 곱셈

링크: www.acmicpc.net/problem/2740

2740번: 행렬 곱셈

배준 단계별 분류 분할정복을 풀던 중 브론즈 문제가 나왔는데,

다음 문제도 행렬 곱셈을 활용하기 때문에 먼저 풀어봤다.

import java.io.*;
import java.util.*;
public class Main {

	public static void main(String[] args) throws Exception {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		StringTokenizer st = new StringTokenizer(br.readLine());
		int [][]A; int [][]B;
		int N,M,K;
		N = Integer.parseInt(st.nextToken());
		M = Integer.parseInt(st.nextToken());
		A = new int[N][M];
		
		for(int i=0;i<N;i++) {
			st =  new StringTokenizer(br.readLine());
			for(int j=0;j<M;j++) {
				A[i][j] = Integer.parseInt(st.nextToken());
			}
		}
		st = new StringTokenizer(br.readLine());
		st.nextToken();
		K = Integer.parseInt(st.nextToken());
		B = new int[M][K];
		for(int i=0;i<M;i++) {
			st = new StringTokenizer(br.readLine());
			int idx= 0;
			while(st.hasMoreElements()) {
				B[i][idx++] = Integer.parseInt(st.nextToken());
			}
		}
		int ans[][] = new int[N][K];
		for(int i=0;i<N;i++) {
			for(int j=0;j<K;j++) {
				for(int k=0;k<M;k++) {
					ans[i][j] += A[i][k]*B[k][j];
				}
			}
		}
		for(int i=0;i<N;i++) {
			for(int j=0;j<K;j++) {
				System.out.print(ans[i][j] + " ");
			}
			System.out.println();
		}
	}

}