LeetCode 344 - Reverse String Problem

Problem Statement

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"]

Solution:

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