sudoku_solution.py

sudoku_solution.py

# %%
from PIL import Image, ImageDraw, ImageFont


def is_valid(board, row, col, num):
    # Check row
    for i in range(9):
        if board[row][i] == num:
            return False

    # Check column
    for i in range(9):
        if board[i][col] == num:
            return False

    # Check 3x3 box
    start_row = (row // 3) * 3
    start_col = (col // 3) * 3
    for i in range(3):
        for j in range(3):
            if board[start_row + i][start_col + j] == num:
                return False

    return True


def solve_sudoku(board, gif_frames):
    display_board_image(board, gif_frames)
    for row in range(9):
        for col in range(9):
            if board[row][col] == 0:
                for num in range(1, 10):
                    if is_valid(board, row, col, num):
                        board[row][col] = num
                        if solve_sudoku(board, gif_frames):
                            return True
                        board[row][col] = 0
                return False
    return True


def display_board_image(board, gif_frames):
    cell_size = 50
    grid_size = cell_size * 9
    image = Image.new("RGB", (grid_size, grid_size), color="white")
    draw = ImageDraw.Draw(image)
    font = ImageFont.truetype("Arial Unicode.ttf", 60)

    # 外側の縁を描画
    draw.rectangle((0, 0, grid_size - 1, grid_size - 1), outline="black", width=2)

    for i in range(9):
        for j in range(9):
            if board[i][j] != 0:
                x = j * cell_size + cell_size // 2
                y = i * cell_size + cell_size // 2
                draw.text(
                    (x, y), str(board[i][j]), font=font, anchor="mm", fill="black"
                )

    for i in range(10):
        line_width = 2 if i % 3 == 0 else 1
        draw.line(
            (0, i * cell_size, grid_size, i * cell_size), fill="black", width=line_width
        )
        draw.line(
            (i * cell_size, 0, i * cell_size, grid_size), fill="black", width=line_width
        )

    # 外側の縁をもう一度描画
    draw.rectangle((0, 0, grid_size - 1, grid_size - 1), outline="black", width=2)

    gif_frames.append(image)


def save_gif(gif_frames, filename, duration=500, last_frame_duration=10000):
    # 最後のフレームを複製
    last_frame = gif_frames[-1].copy()

    # 最後のフレームを追加
    gif_frames.append(last_frame)

    # フレームの表示時間を設定
    durations = [duration] * (len(gif_frames) - 1) + [last_frame_duration]

    gif_frames[0].save(
        filename,
        save_all=True,
        append_images=gif_frames[1:],
        optimize=False,
        duration=durations,
        loop=0,
    )


board = [
    [8, 0, 0, 0, 0, 0, 0, 0, 0],
    [0, 0, 3, 6, 0, 0, 0, 0, 0],
    [0, 7, 0, 0, 9, 0, 2, 0, 0],
    [0, 5, 0, 0, 0, 7, 0, 0, 0],
    [0, 0, 0, 0, 4, 5, 7, 0, 0],
    [0, 0, 0, 1, 0, 0, 0, 3, 0],
    [0, 0, 1, 0, 0, 0, 0, 6, 8],
    [0, 0, 8, 5, 0, 0, 0, 1, 0],
    [0, 9, 0, 0, 0, 0, 4, 0, 0],
]

gif_frames = []
solve_sudoku(board, gif_frames)
save_gif(gif_frames, "sudoku_solution.gif", duration=5)