generate.py

def generate(n_rows, n_cols, ratio, diff):
    hidato_solved = generate_hidato_solved(n_rows, n_cols, ratio)
    max_elem = n_rows * n_cols - count_obstacles(hidato_solved)
    cells_for_remove = random_shuffle(filter(lambda cell: get_cell_value(cell) > 1 and get_cell_value(cell) < max_elem, get_cells(hidato_solved)))
    cant_empty = floor(len(cells_for_remove) * diff)
    template = remove_cells(hidato_solved, n_rows, n_cols, cells_for_remove, cant_empty)
    return template


def generate_hidato_solved(n_rows, n_cols, ratio):
    pseudo_template = generate_random_pseudo_template(n_rows, n_cols, ratio)
    limit = n_rows * n_cols - count_obstacles(pseudo_template)
    solves = solve(pseudo_template, 0, limit)
    if solves:
        return solves[0]
    else:
        return generate_hidato_solved(n_rows, n_cols, ratio)


def generate_random_pseudo_template(n_rows, n_cols, ratio):
    cant_obs = floor(n_rows * n_cols * ratio)
    blank_template = create_black_template(n_rows, n_cols)
    cells_for_remove = take(cant_obs, random_shuffle(get_cells(blank_template)))
    dark_template = reduce(lambda acc, cell: update_cell_in_table(acc, update_value_in_cell(-1, cell)), cells_for_remove, blank_template)
    pseudo_template = update_cell_in_table(dark_template, update_value_in_cell(1, select_random_cell(dark_template)))
    return pseudo_template


def remove_cells(template, n_rows, n_cols, cells_for_remove, cant_empty):
    if not cells_for_remove or cant_empty < 0:
        return template
    else:
        head_cell = cells_for_remove[0]
        tail_cells = cells_for_remove[1:]
        empty = update_value_in_cell(0, head_cell)
        new_template = update_cell_in_table(template, empty)
        limit = n_rows * n_cols - count_obstacles(new_template)
        solves = solve(new_template, 0, limit)
        if len(take(2, solves)) < 2:
            return remove_cells(new_template, n_rows, n_cols, tail_cells, cant_empty - 1)
        else:
            return remove_cells(template, n_rows, n_cols, tail_cells, cant_empty)