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:
Input: A = [ [ 1, 0, 0], [-1, 0, 3] ] B = [ [ 7, 0, 0 ], [ 0, 0, 0 ], [ 0, 0, 1 ] ] Output: | 1 0 0 | | 7 0 0 | | 7 0 0 | AB = | -1 0 3 | x | 0 0 0 | = | -7 0 3 | | 0 0 1 |
Constraints:
1 <= A.length, B.length <= 100
1 <= A[i].length, B[i].length <= 100
-100 <= A[i][j], B[i][j] <= 100
A:
实现题
class Solution { public: vector<vector<int>> multiply(vector<vector<int>>& A, vector<vector<int>>& B) { int m = A.size(); if (m == 0) { return vector<vector<int>>(); } int n = A[0].size(); int k = B[0].size(); vector<vector<int>> res(m, vector<int>(k, 0)); for (int i = 0; i < m; i++) { for (int j = 0; j < k; j++) { for (int t = 0; t < n; t++) { res[i][j] += A[i][t] * B[t][j]; } } } return res; } };
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