2048.py

from itertools import groupby, chain

LOSE = [['G', 'A', 'M', 'E'], ['O', 'V', 'E', 'R'], ['G', 'A', 'M', 'E'], ['O', 'V', 'E', 'R']]
WIN = [['U', 'W', 'I', 'N'], ['U', 'W', 'I', 'N'], ['U', 'W', 'I', 'N'], ['U', 'W', 'I', 'N']]
    
def collide_row(row):
    tiles = []
    for k,g in groupby(filter(bool,row)):
        l = len(list(g))
        if l % 2:
            tiles.append(k)
        tiles.extend([k*2]*(l/2))    
    return [0]*(len(row)-len(tiles))+tiles

def put_last_tile(S):
    l = len(S)-1
    for i in xrange(l, -1, -1):
        for j in xrange(l, -1, -1):
            if S[i][j] == 0:
                S[i][j] = 2
                return True
    return False
    
def move2048(state, move):
    if move == "right":
        new_state = [ collide_row(row) for row in state ]
    if move == "left":
        new_state = [ collide_row(row[::-1])[::-1] for row in state ]
    if move == "down":
        new_state = map(list,zip(*[ collide_row(column) for column in zip(*state) ]))
    if move == "up":
        new_state = map(list,zip(*[ collide_row(column[::-1])[::-1] for column in zip(*state) ]))
    if 2048 in chain.from_iterable(new_state):
        return WIN
    if put_last_tile(new_state):
        return new_state
    else:
        return LOSE