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.
Constraints:
2 <= s.length <= 1000s.length is even.s consists of uppercase and lowercase letters.class Solution {
public:
bool halvesAreAlike(string s) {
unordered_set <char> vowel = {'a','e','i','o','u','A','E','I','O','U'};
int last = s.size()-1, half=s.size()/2, ctA=0, ctB=0;
for(int i=0; i<half; i++){
if(vowel.find(s[i])!=vowel.end())
ctA++;
if(vowel.find(s[last-i])!=vowel.end())
ctB++;
}
return ctA==ctB;
}
};