leetcode with python:344. Reverse String

题目:

Write a function that reverses a string. The input string is given as an array of characters s.

You must do this by modifying the input array in-place with O(1) extra memory.

给定一个由字元组成的阵列,将其反转
题目限制我们的空间複杂度只能是O(1)

这题用简单的two pointer就能解决

class Solution:    def reverseString(self, s: List[str]) -> None:        """        Do not return anything, modify s in-place instead.        """        l=0        r=len(s)-1        while l<r:            temp=s[l]            s[l]=s[r]            s[r]=temp            l=l+1            r=r-1

设立两个指标(l,r),一个从阵列头,一个从阵列尾开始走
路上不断交换值直到两者相遇或交错
我们就成功反转该阵列了
最后执行时间197ms(faster than 98.06%)

那我们下题见