2740번 행렬 곱셈

문제 

 

 

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문제 풀이

public class Main {
	public static StringBuilder sb = new StringBuilder();
	public static void main(String[] args) throws IOException {
		BufferedReader bf = new BufferedReader(new InputStreamReader(System.in));
		StringTokenizer st = new StringTokenizer(bf.readLine());
		int n = Integer.parseInt(st.nextToken());
		int m = Integer.parseInt(st.nextToken());
		int [][] arr = new int[n][m];
		for (int i = 0; i < n; i++) {
			st = new StringTokenizer(bf.readLine());
			for (int j = 0; j < m; j++) {
				arr[i][j] = Integer.parseInt(st.nextToken());
			}
		}
		st = new StringTokenizer(bf.readLine());
		m = Integer.parseInt(st.nextToken());
		int k = Integer.parseInt(st.nextToken());
		int [][] arr2 = new int[m][k];
		for (int i = 0; i < m; i++) {
			st = new StringTokenizer(bf.readLine());
			for (int j = 0; j < k; j++) {
				arr2[i][j] = Integer.parseInt(st.nextToken());
			}
		}
		int [][] result = new int[n][k];
		for (int i = 0; i < n; i++) {
			for (int j = 0; j < k; j++) {
				int sum = 0;
				for(int l = 0; l < m; l++) {
					sum += arr[i][l] * arr2[l][j];
				}
				sb.append(sum).append(' ');
			}
			sb.append('\n');
		}
		System.out.println(sb.toString());
	}
}