int main(){int arr[M][M] = {{12, -6, 6, 8, 1},{8, 7, -6, 5, 3},{0, 7, -6, -9, 4},{1, -10, -8, 8, 5},{6, -4, 2, 5, 3},};int i, j, k;int sum, ok, * sums, sum_index;int min_elem;for (j = 0; j < M; j++) {ok = 1;sum = 0;for (k = 0; k < M; k++) {if (arr[k][j] < 0) {ok = 0;break;}sum += arr[k][j];}if (ok) {printf("stolbec: %d, sum: %dn", j + 1, sum);}}sums = (int*)malloc(sizeof(int) * (M - 1) * 2);if (sums == NULL) {exit(EXIT_FAILURE);}sum_index = 0;Обьясните , что делает данная строчка sums = (int*)malloc(sizeof(int) * (M - 1) * 2);