Determine if String Halves Are Alike

Problem Statement:

You are given a string s of even length. Split this string into two halves of equal lengths, and let a be the first half and b be the second half.
Two strings are alike if they have the same number of vowels ('a', 'e', 'i', 'o', 'u', 'A', 'E', 'I', 'O', 'U'). Notice that s contains uppercase and lowercase letters.
Return true if a and b are alike. Otherwise, return false.

 
Example 1:
Input: s = "book"
Output: true
Explanation: a = "bo" and b = "ok". a has 1 vowel and b has 1 vowel. Therefore, they are alike.

Example 2:
Input: s = "textbook"
Output: false
Explanation: a = "text" and b = "book". a has 1 vowel whereas b has 2. Therefore, they are not alike.
Notice that the vowel o is counted twice.

Example 3:
Input: s = "MerryChristmas"
Output: false

Example 4:
Input: s = "AbCdEfGh"
Output: true


Solution:
class Solution:
    def halvesAreAlike(self, s: str) -> bool:
        
        ###### O(N)
        
        start=0
        end=len(s)-1
        
        acount=0
        bcount=0
        
        while start<end:
            if s[start] in "aeiouAEIOU":
                acount+=1
                
            if s[end] in "aeiouAEIOU":
                bcount+=1
                
            start+=1    
            end-=1
            
        return acount==bcount