void fill(int *v, char **map, int nr_of_lines, int i, int j, int *count) {
    // check if we landed on a correct spot, return otherwise
    if (i < 0 || j < 0 || i >= nr_of_lines || j >= v[i] * 4 || map[i][j] != 0)
        return;
    // mark the spot and go again in each direction
    map[i][j] = 0x01;
    (*count)++;
    fill(v, map, nr_of_lines, i + 1, j, count);
    fill(v, map, nr_of_lines, i, j + 1, count);
    fill(v, map, nr_of_lines, i - 1, j, count);
    fill(v, map, nr_of_lines, i, j - 1, count);
}