一道python走迷宫算法题

# _*_ coding:utf-8 _*_  
route_stack = [[0,0]] 
route_history = [[0,0]] 
source=[[0,0,1,0,1],[1,0,0,0,1],[0,0,1,1,0],[0,1,0,0,0],[0,0,0,1,0]] 
def up(location): 
  #横坐标为0，无法再向上走 
  if location[1] == 0: 
    return False 
  else: 
    new_location = [location[0],location[1]-1] 
    #已经尝试过的点不会尝试第二次 
    if new_location in route_history: 
      return False 
    #碰到墙不走 
    elif source[new_location[0]][new_location[1]] == 1: 
      return False 
    else: 
      route_stack.append(new_location) 
      route_history.append(new_location) 
      return True 
 
def down(location): 
  if location[1] == 4: 
    return False 
  else: 
    new_location = [location[0],location[1]+1] 
    if new_location in route_history: 
      return False 
    elif source[new_location[0]][new_location[1]] == 1: 
      return False 
    else: 
      route_stack.append(new_location) 
      route_history.append(new_location) 
      return True 
 
def left(location): 
  if location[0] == 0: 
    return False 
  else: 
    new_location = [location[0]-1,location[1]] 
    if new_location in route_history: 
      return False 
    elif source[new_location[0]][new_location[1]] == 1: 
      return False 
    else: 
      route_stack.append(new_location) 
      route_history.append(new_location) 
      return True 
 
def right(location): 
  if location[0] == 4: 
    return False 
  else: 
    new_location = [location[0]+1,location[1]] 
    if new_location in route_history: 
      return False 
    elif source[new_location[0]][new_location[1]] == 1: 
      return False 
    else: 
      route_stack.append(new_location) 
      route_history.append(new_location) 
      return True 
lo = [0,0] 
while route_stack[-1] != [4,4]: 
  if up(lo): 
    lo = route_stack[-1] 
    continue 
  if down(lo): 
    lo = route_stack[-1] 
    continue 
  if left(lo): 
    lo = route_stack[-1] 
    continue 
  if right(lo): 
    lo = route_stack[-1] 
    continue 
  route_stack.pop() 
  lo = route_stack[-1] 
print route_stack