백준 알고리즘 10866번

백준링크

deque 활용하여 구현하기

파이썬

from collections import deque
import sys
input = sys.stdin.readline
n = int(input())
q = deque()
for _ in range(n):
    a = input().split()
    if a[0] == "push_front":
        q.appendleft(a[1])
    elif a[0] == "push_back":
        q.append(a[1])
    elif a[0] == "pop_front":
        if q:
            print(q[0])    
            q.popleft()
        else:
            print("-1")
    elif a[0] == "pop_back":
        if q:
            print(q[len(q) - 1])    
            q.pop()
        else:
            print("-1")
    elif a[0] == "size":
        print(len(q))
    elif a[0] == "empty":
        if q:
            print("0")
        else:
            print("1")
    elif a[0] == "front":
        if q:
            print(q[0])
        else:
            print("-1")
    elif a[0] == "back":
        if q:
            print(q[len(q) - 1])
        else:
            print("-1")