https://leetcode-cn.com/problems/reverse-string/
class Solution:
def reverseString(self, s: List[str]) -> None:
i=0
j=-1
while i<len(s)/2:
s[i],s[j]=s[j],s[i]
i+=1
j-=1
代码比较简短,主要是因为python太好用了。。。