Python - Leetcode : Day 1

leetcode -> 344 -reverse string

344 - Reverse string -

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

sol 1 - Pattern 'Stack' - Using a stack DS , but it uses O(N) extra memory.

sol 2 - 2 Pointer Approach - Using Two Pointers there is no need of Extra Memory
time complexity -O(N)
space complexity -O(1)

Code -

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