import time

# Das Sudoku-Startfeld
start = [
    [0, 8, 0, 0, 2, 0, 5, 6, 0],
    [0, 0, 0, 1, 0, 0, 0, 0, 7],
    [0, 0, 0, 0, 0, 0, 0, 0, 0],
    [0, 5, 0, 0, 9, 0, 4, 0, 8],
    [0, 0, 7, 8, 0, 0, 0, 0, 3],
    [0, 9, 0, 0, 1, 0, 0, 5, 0],
    [2, 0, 4, 0, 0, 0, 8, 0, 0],
    [0, 6, 0, 0, 8, 5, 0, 0, 0],
    [0, 0, 0, 2, 0, 0, 1, 0, 0]
]

def isfine(feld, x, y):
    # Doppelte Zahl in Zeile oder Spalte prüfen
    for yi in range(9):
        if yi != y and feld[x][yi] == feld[x][y]:
            return False
    for xi in range(9):
        if xi != x and feld[xi][y] == feld[x][y]:
            return False

    # Neuner-Kästchen-Test
    x1 = (x // 3) * 3
    y1 = (y // 3) * 3
    for xk in range(x1, x1 + 3):
        for yk in range(y1, y1 + 3):
            if (xk != x or yk != y) and feld[xk][yk] == feld[x][y]:
                return False

    return True

def nextone(feld, x, y):
    if y == 9:
        y = 0
        x += 1
    if x == 9:
        return True

    if feld[x][y] > 0:
        if not isfine(feld, x, y):
            return False
        return nextone(feld, x, y + 1)
    else:
        for feld[x][y] in range(1, 10):
            if not isfine(feld, x, y):
                continue
            if nextone(feld, x, y + 1):
                return True
        feld[x][y] = 0
        return False

def main():
    tstart = time.time()
    
    if nextone(start, 0, 0):
        for row in start:
            print(row)
    else:
        print("Nope!")

    time1 = time.time()
    print(f"{tstart} - {time1} * {time.CLOCKS_PER_SEC}")

if __name__ == "__main__":
    main()