[백준] 18258번 큐 2 / 파이썬(python)

# 문제 링크

www.acmicpc.net/problem/18258

18258번: 큐 2

# Soultion

import sys
from collections import deque
 
n = int(input())
q = deque()
 
for _ in range(n):
    cmd = list(map(str, sys.stdin.readline().split()))
    if cmd[0]=='push':
        q.append(cmd[1])
    elif cmd[0]=='pop':
        if q:
            print(q.popleft())
        else:
            print("-1")
    elif cmd[0]=='size':
        print(len(q))
    elif cmd[0]=='empty':
        if len(q)==0:
            print(1)
        else:
            print(0)
    elif cmd[0]=='front':
        if q:
            print(q[0])
        else:
            print("-1")
    elif cmd[0]=='back':
        if q:
            print(q[-1])
        else:
            print("-1")