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  1. import java.util.Scanner;
  2. public class Main {
  3. 	public static void main(String[] args) {
  4. 		Scanner scanner = new Scanner(System.in);
  5. 		int na = scanner.nextInt();
  6. 		int ma = scanner.nextInt();
  7. 		int[][] a = new int[na][ma];
  8. 		for (int i = 0; i < na; i++) {
  9. 			for (int j = 0; j < ma; j++) {
  10.             			a[i][j] = scanner.nextInt();
  11. 			}
  12. 		}
  13. 		int nb = scanner.nextInt();
  14. 		int mb = scanner.nextInt();
  15. 		if (ma != nb) {
  16. 			System.out.print(-1);
  17. 			return;
  18. 		}
  19. 		int[][] b = new int[nb][mb];
  20. 		for (int i = 0; i < nb; i++) {
  21. 			for (int j = 0; j < mb; j++) {
  22. 				b[i][j] = scanner.nextInt();
  23. 			}
  24. 		}
  25. 		int[][] c = new int[na][mb];
  26. 		for (int i = 0; i < na; i++) {
  27. 			for (int j = 0; j < mb; j++) {
  28. 				for (int r = 0; r < ma; r++) {
  29. 					c[i][j] += a[i][r] * b[r][j];
  30. 				}
  31. 			}
  32. 		}
  33. 		System.out.print(na + " " + mb + "\n");
  34. 		for (int i = 0; i < na; i++) {
  35. 			for (int j = 0; j < mb; j++) {
  36. 				System.out.print(c[i][j]);
  37. 				if (j + 1 != mb) System.out.print(" ");
  38. 			}
  39. 			System.out.print("\n");
  40. 		}
  41. 	}
  42. }
Success #stdin #stdout 0.07s 2184192KB
comments (?)
stdin 
4 4
4 8 -18 16
3 7 14 -42
2 1 1 7
4 9 5 -2
4 4
1 0 0 0
0 1 0 0
0 0 1 0
0 0 0 1
stdout 
4 4
4 8 -18 16
3 7 14 -42
2 1 1 7
4 9 5 -2
https://ideone.com/BbTsEP
matrix multiplication java
language:
Java (HotSpot 12)
created:
5 years ago
visibility:
public

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