代码

#define idx(i, j) ((i) * n + (j))

void matrix_multiply(int n, const int *A, const int *B, int *C) {
	for (int i = 0; i < n; i++) {
		for (int k = 0; k < n; k++) {
			for (int j = 0; j < n; j++) {
				C[idx(i, j)] += (unsigned)A[idx(i, k)] * B[idx(k, j)];
			}
		}
	}
}

评测结果