leetcode 344. 反转字符串 python

题目描述：

题解：

双指针left从下标0开始，right从len(s)-1开始

每次交换s[left] s[right]，left++ right--

class Solution(object):
    def reverseString(self, s):
        left = 0
        right = len(s)-1
        while left<=right:
            s[left],s[right] = s[right],s[left]
            left = left+1
            right = right-1
        return s