Given two sparse matrices A and B, return the result of AB.
You may assume that A‘s column number is equal to B‘s row number.
Example:
A = [ [ 1, 0, 0], [-1, 0, 3] ] B = [ [ 7, 0, 0 ], [ 0, 0, 0 ], [ 0, 0, 1 ] ] | 1 0 0 | | 7 0 0 | | 7 0 0 | AB = | -1 0 3 | x | 0 0 0 | = | -7 0 3 | | 0 0 1 |
public class Solution { public int[][] multiply(int[][] A, int[][] B) { int ma = A.length; int na = A[0].length; int mb = B.length; //na = mb int nb = B[0].length; int[][] C = new int[ma][nb]; for(int i=0; i<ma;i++) { for(int k=0; k<na;k++) { if (A[i][k] != 0) { for (int j = 0; j < nb; j++) { if (B[k][j] != 0) C[i][j] += A[i][k] * B[k][j]; } } } } return C; } }
reference: https://leetcode.com/discuss/71912/easiest-java-solution
时间: 2024-10-11 23:02:14