Leetcode 344. reverse string

Power button | 344. Reverse string

  Method ： Double pointer

Simple questions, punch hard ！

Use double pointers directly , Move from both sides to the middle , Swap the elements pointed to by the left and right pointers , Complete inversion .

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

Complete test code

from typing import List

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

class main:
    a = Solution()
    s = ["h","e","l","l","o"]
    print(s)
    b=a.reverseString(s)
    print(s)


if __name__ == '__main__':
    main()