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.
Example 1:
Input: s = [“h”,“e”,“l”,“l”,“o”]
Output: [“o”,“l”,“l”,“e”,“h”]
Example 2:
Input: s = [“H”,“a”,“n”,“n”,“a”,“h”]
Output: [“h”,“a”,“n”,“n”,“a”,“H”]
https://leetcode.cn/problems/reverse-string/solutions/2376290/ji-chong-bu-tong-de-xie-fa-pythonjavacgo-9trb/
思路一：快慢指针
class Solution:def reverseString(self, s: List[str]) -> None:left = 0right = len(s) - 1while left < right:s[left], s[right] = s[right], s[left]left += 1right -= 1
思路二：循环
class Solution:def reverseString(self, s: List[str]) -> None:for i in range(len(s) // 2):s[i], s[-i - 1] = s[-i - 1], s[i]
思路三：使用语法糖
class Solution:def reverseString(self, s: List[str]) -> None:# s[:] = s[::-1] 是切片赋值语法，表示用 s[::-1] 替换 s 中的元素。# 注意不能写成 s = s[::-1]，因为 s 只是形参，修改 s 不会影响函数外部传入的实参。# 注意这不是原地操作，需要 O(n) 额外空间。s[:] = s[::-1]
