Blogs Hub

by Sumit Chourasia | Jan 08, 2021 | Category :coding | Tags : algorithm data-structure easy leetcode string

Determine if String Halves Are Alike - String - Easy - LeetCode

Determine if String Halves Are Alike - String - Easy - LeetCode

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
 

Constraints:

2 <= s.length <= 1000
s.length is even.
s consists of uppercase and lowercase letters.

 

public class Solution {
    public bool HalvesAreAlike(string s) {
        int vowel = 0;    
        
        for(int i=0;i<s.Length/2;i++){
            if(IsVowel(s[i])){
                vowel++;
            }
        }
        
        for(int i=s.Length/2;i<s.Length;i++){
            if(IsVowel(s[i])){
                vowel--;
            }
        }
        
        return vowel==0;
    }
    
    private bool IsVowel(char ch){
        if(ch=='a'||ch=='A'||ch=='e'||ch=='E'||ch=='i'||ch=='I'||ch=='o'||ch=='O'||ch=='u'||ch=='U'){
            return true;
        }
        return false;
    }
}

Time Complexity: O(n)

Space Complexity: O(1)