345. Reverse Vowels of a String

class Solution {
    public String reverseVowels(String s) {
        int len = s.length();
        int left = 0;
        int right = len - 1;
        char c[] = s.toCharArray();
        
        while (left < right) {
            while (left < right && !isVowel(c[left])) {
                left++;
            }
            
            while (left < right && !isVowel(c[right])) {
                right--;
            }
            
            if (left < right) {
                swap(c, left, right);
            }
            left++;
            right--;
        }
        return String.valueOf(c);
    }
    
    private void swap(char[] c, int left, int right) {
        char temp = c[left];
        c[left] = c[right];
        c[right] = temp;
    }
    
    private boolean isVowel(char c) {
        return (c == 'a' || c == 'e' || c == 'i' || c == 'o' || c == 'u' ||
                c == 'A' || c == 'E' || c == 'I' || c == 'O' || c == 'U');
    }
}