[LeetCode] 344. Reverse String

 Problem : https://leetcode.com/problems/reverse-string/

An uncommon 2 pointers approach.

class Solution:
    def reverseString(self, s: List[str]) -> None:
        """
        Do not return anything, modify s in-place instead.
        """
        N = len(s)
        for i in range(N//2):
            j = N - i - 1
            s[i], s[j] = s[j], s[i]