2048

#!/usr/bin/env python3
import random


def seed(grid):
    for i in range(3, 0, -1):
        if 0 in grid[i]:
            r = random.randrange(4)
            while grid[i][r] != 0:
                r = random.randrange(4)
            grid[i][r] = random.randrange(1, 3)
            return False
    else:
        return True

def left(grid, reverse=False):
    moved = 0
    for i in range(len(grid)):
        grid[i] = list(filter(lambda a: a, grid[i]))
        if reverse:
            grid[i] = (4 - len(grid[i])) * [0] + grid[i]
        else:
            grid[i] += (4 - len(grid[i])) * [0]
        for j in range(len(grid[i])):
            if j < len(grid[i]) - 1 and grid[i][j] == grid[i][j + 1] and grid[i][j]:
                if reverse:
                    grid[i][j + 1] *= 2
                    grid[i][j] = 0
                else:
                    grid[i][j] *= 2
                    grid[i][j + 1] = 0
                moved += 1
    return left(grid, reverse) if moved else grid

def up(grid, reverse=False):
    grid = [list(row) for row in list(zip(*grid))]
    grid = left(grid, reverse)
    grid = [list(row) for row in list(zip(*grid))]
    return grid

def print_grid(grid):
    for row in grid:
        print(row)

grid = [[0 for i in range(4)] for j in range(4)]

while True:
    final = seed(grid)
    if final:
        print("Game over")
        break
    print_grid(grid)
    command = input()
    if command == 'up':
        grid = up(grid)
    elif command == 'down':
        grid = up(grid, True)
    elif command == 'left':
        grid = left(grid)
    else:
        grid = left(grid, True)