[백준] 1697<DFS/BFS> 숨바꼭질 - python

이게 왜 틀리지..

 

from collections import deque

start, goal = map(int,input().split())
q = deque()
q.append(start)      
time = [0] * (goal+2)

def bfs():
  while q:
    x = q.popleft()
  
    for i in (x-1, x+1, x*2):
      if i == goal:
        print(time[x] + 1)
        return
      if 0 <= i <= (goal+1):
        if time[i] == 0:
          time[i] = time[x] + 1
          q.append(i)


if start > goal:
  print(start - goal)
else:
  bfs()