用python3提交：

有时TLE#19#20#21#22.

有时TLE#19#20#21.

无奈，

之后又用pypy3提交：

TLE#19.

这真的是Python的极限吗？

求优化！！！

附代码：

from collections import deque

def f(q, c, i, v=None):
    if c == 'push_back':
        q[i].append(v)
    elif c == 'pop_back':
        if q[i]:
            q[i].pop()
    elif c == 'push_front':
        q[i].appendleft(v)
    elif c == 'pop_front':
        if q[i]:
            q[i].popleft()
    elif c == 'size':
        print(len(q[i]))
    elif c == 'front':
        if q[i]:
            print(q[i][0])
    elif c == 'back':
        if q[i]:
            print(q[i][-1])

def main():
    n = int(input())
    q = {}
    for _ in range(n):
        s = input()
        pt = s.split()
        c = pt[0]
        i = int(pt[1]) - 1
        v = pt[2] if len(pt) > 2 and c in ['push_back', 'push_front'] else None
        if i not in q:
            q[i] = deque()
        f(q, c, i, v)

if __name__ == "__main__":
    main()