题目：反转字符串

Write a function that takes a string as input and returns the string reversed.

Example:

Given s = "hello", return "olleh".

五种解法：

#直接逆序class Solution(object):    def reverseString(s):        return s[::-1]

耗时56ms

#前后对称位互换class Solution(object):    def reverseString(s):        li = list(s)        l = len(s)        for i, j in zip(range(len(l)-1, 0, -1), range(l//2)):             li[i], li[j] = li[j], li[i]        reurn ''.join(li)

耗时52ms

#递归 逐个逆转class Solution(object):    def reverseString(s):        if len(s) <=1:            return s        return self.reverseString(s[1:]) + s[0]

耗时64ms

#使用队列class Solution(object):    def reverseString(s):        from collections import deque        q = deque()        q.extendleft(s)        return ''.join(q)

耗时60ms

#循环逆序class Solution(object):    def reverseString(s):        return ''.join([s[i] for i in range(len(s)-1,-1,-1)])

耗时52ms