[자료구조/python]백준 10845번 큐

import sys

n=int(sys.stdin.readline())

list=[]
answer=[]

for _ in range(n):
  list=sys.stdin.readline().split()
  if list[0]=='push':
    answer.append(list[1])
  elif list[0]=='pop':
    if len(answer)==0:
      print(-1)
    else:
      print(answer.pop(0))
  elif list[0]=='size':
    print(len(answer))
  elif list[0]=='empty':
    if len(answer)==0:
      print(1)
    else:
      print(0)
  elif list[0]=='front':
    if len(answer)==0:
      print(-1)
    else:
      print(answer[0])
  elif list[0]=='back':
    if len(answer)==0:
      print(-1)
    else:
      print(answer[-1])