Maximum Number of Vowels in a Substring of Given Length | LeetCode | Java

Set<Character> set = new HashSet<>();

set.add(‘a’);
set.add(‘e’);
set.add(‘i’);
set.add(‘o’);
set.add(‘u’);

char arr[] = s.toCharArray();

int count = 0, maxCount = 0;

for(int i=0; i<k; i++){
if(set.contains(arr[i]))
count++;
}

maxCount = count;

int n = arr.length;

for(int i=k; i<n; i++){
if(set.contains(arr[i]))
count++;
if(set.contains(arr[i-k]))
count–;

maxCount = Math.max(count, maxCount);
}

return maxCount;

}
}