0344-Reverse-String.py

'''
Write a function that reverses a string. The input string is given as an array of characters char[].

Do not allocate extra space for another array, you must do this by modifying the input array in-place with O(1) extra memory.

You may assume all the characters consist of printable ascii characters.



Example 1:

Input: ["h","e","l","l","o"]
Output: ["o","l","l","e","h"]
Example 2:

Input: ["H","a","n","n","a","h"]
Output: ["h","a","n","n","a","H"]
'''

# Without returning anything and modifying in place

class Solution:
    def reverseString(self, s: List[str]) -> None:
        start, end = 0, len(s) - 1
        while start < end:
            s[start], s[end] = s[end], s[start]
            start += 1
            end -= 1