Python深度优先算法生成迷宫

import random 
 
#warning: x and y confusing 
 
sx = 10 
sy = 10 
dfs = [[0 for col in range(sx)] for row in range(sy)] 
maze = [[' ' for col in range(2*sx+1)] for row in range(2*sy+1)] 
#1:up 2:down 3:left 4:right 
operation = {1:(0,-1),2:(0,1),3:(-1,0),4:(1,0)} 
direction = [1,2,3,4] 
stack = [] 
 
for i in range(2*sx+1): 
 if i%2 == 0: 
  for j in range(2*sx+1): 
   maze[i][j] = '#' 
for i in range(2*sy+1): 
 if i%2 == 0: 
  for j in range(2*sy+1): 
   maze[j][i] = '#' 
 
def show(graph): 
 for i in graph: 
  for j in i: 
   print j,print 
 
def showRouter(stack): 
 RGragh = [[0 for col in range(sx)] for row in range(sy)] 
 for (x,y) in stack: 
  RGragh[y][x] = 1 
 show(RGragh) 
 print 
 
def generateMaze(start): 
 x,y = start 
 dfs[y][x] = 1 
 random.shuffle(direction) 
 for d in direction: 
  px,py = (x + y for x,y in zip(start,operation[d])) 
  if px < 0 or px >= sx or py < 0 or py >= sy: 
   pass 
  else: 
   if dfs[py][px] is not 1: 
    mx = 2*x + 1 
    my = 2*y + 1 
    if d == 1: 
     maze[my-1][mx] = ' ' 
    elif d == 2: 
     maze[my+1][mx] = ' ' 
    elif d == 3: 
     maze[my][mx-1] = ' ' 
    elif d == 4: 
     maze[my][mx+1] = ' ' 
    generateMaze((px,py)) 
 
generateMaze((0,0)) 
show(dfs) 
show(maze)