Sudoku Solver - On the Air

sudoku_solver_onair.py

import random

def print_puzzle(puzzle):
    print('---' * 18)
    for row in range(9):
        for col in range(9):
            pos = row * 9 + col
            print(' ', puzzle[pos]['val'], end=' |')
        print(end='\n')
        if (row + 1) % 3 == 0:
            print('---' * 18)

def init_puzzle(seed_values):
    row_axis = []
    col_axis = []
    box_axis = []
    for row in range(9):
        row_axis.append([1, 2, 3, 4, 5, 6, 7, 8, 9])
        col_axis.append([1, 2, 3, 4, 5, 6, 7, 8, 9])
        box_axis.append([1, 2, 3, 4, 5, 6, 7, 8, 9])
    puzzle = []
    for item in range(81):
        row = item // 9
        col = item % 9
        if row < 3:
            box = 0
        elif row < 7:
            box = 3
        else:
            box = 6
        if col < 3:
            box += 0
        elif col < 7:
            box += 1
        else:
            box += 2
        cell = {}
        cell['val'] = 0
        cell['col'] = col
        cell['row'] = row
        cell['box'] = box
        puzzle.append(cell)
    for row, col, seed_num in seed_values:
        # print(row, col, seed_num)
        pos = (row * 9) + col
        cell = puzzle[pos]
        if seed_num in row_axis[cell['row']] and seed_num in col_axis[cell['col']] and seed_num in box_axis[cell['box']]:
            row_axis[cell['row']].remove(seed_num)
            col_axis[cell['col']].remove(seed_num)
            box_axis[cell['box']].remove(seed_num)
            cell['val'] = seed_num
        else:
            print('invalid seed: ', row, col, seed_num)
    return puzzle, row_axis, col_axis, box_axis

def _get_valid_choices(row_values, col_values, grid_values):
    valid_choices = []
    for val in range(1, 10):
        if val in row_values and val in col_values and val in grid_values:
            valid_choices.append(val)
    return valid_choices

def solve_puzzle(init_seed):
    prob_puzzle, prob_row_axis, prob_col_axis, prob_box_axis = init_puzzle(init_seed)
    success = False
    attempts = 0
    while not success and attempts < 10000:
        success = True
        attempts += 1
        puzzle = []
        row_axis = []
        col_axis = []
        box_axis = []
        for item in range(81):
            puzzle.append(prob_puzzle[item].copy())
        for idx in range(9):  # Deep Copy
            row_axis.append(prob_row_axis[idx].copy())
            col_axis.append(prob_col_axis[idx].copy())
            box_axis.append(prob_box_axis[idx].copy())
        for row in range(9):
            for col in range(9):
                pos = (row * 9) + col
                cell = puzzle[pos]
                if cell['val'] == 0:
                    valid_choices = _get_valid_choices(row_axis[cell['row']], col_axis[cell['col']], box_axis[cell['box']])
                    if valid_choices:
                        val = random.choice(valid_choices)
                        cell['val'] = val
                        row_axis[cell['row']].remove(val)
                        col_axis[cell['col']].remove(val)
                        box_axis[cell['box']].remove(val)
                if cell['val'] == 0:
                    # print('Failed at: ', row, col)
                    # print_puzzle(puzzle)
                    # print(row_nums)
                    # print(col_nums)
                    success = False
                    break
            if not success:
                break
    return puzzle, success, attempts

def main():
    init_seed = [(0, 0, 2), (0, 1, 5), (0, 4, 4), (0, 6, 3), \
                (1, 0, 9), (1, 3, 2), (1, 6, 4), \
                (2, 1, 8), (2, 3, 9), (2, 7, 6), \
                (3, 1, 2), (3, 2, 1), (3, 5, 9), (3, 8, 6), \
                (4, 4, 3), \
                (5, 0, 3), (5, 3, 8), (5, 6, 1), (5, 7, 5), \
                (6, 1, 4), (6, 5, 5), (6, 7, 1), \
                (7, 2, 5), (7, 5, 2), (7, 8, 4), \
                (8, 2, 7), (8, 4, 6), (8, 7, 2), (8, 8, 9)]
    puzzle, success, attempts = solve_puzzle(init_seed)
    print('Attempts: ', attempts, ' Found Solution: ', success)
    print_puzzle(puzzle)
    print('Attempts: ', attempts)
if __name__ == '__main__':
    main()