from typing import List

class Solution:
    def reverseString(self, s: List[str]) -> None:
        """
        Do not return anything, modify s in-place instead.
        """
        size = len(s) // 2
        index = 0
        
        while index < size:
            temp = s[index]
            s[index] = s[len(s) - index - 1]
            s[len(s) - index - 1] = temp
            index += 1


def main():
    sol = Solution()
    s = ["h","e","l","l","o"]
    sol.reverseString(s)
    print(s)
    s = ["H","a","n","n","a","h"]
    sol.reverseString(s)
    print(s)

if __name__ == '__main__':
    main()