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Reverse String

Problem Statement​

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.

Leetcode link

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"]

Constraints:​

  • 1 <= s.length <= 105
  • s[i] is a printable ascii character.

Code​

Python Code
class Solution:
    def reverseString(self, s):
        lst = list(s)
        result = []
        i = len(lst)
        while i > 0:
            i -= 1
            result.append(lst[i])
        return "".join(result)