345. Reverse Vowels of a String

Write a function that takes a string as input and reverse only the vowels of a string.

Example 1:
Given s = “hello”, return “holle”.

Example 2:
Given s = “leetcode”, return “leotcede”.

Note:
The vowels does not include the letter “y”.

public class Solution {  
    static final String vowels = "aeiouAEIOU";  
    public String reverseVowels(String s) {  
        int first = 0, last = s.length() - 1;  
        char[] array = s.toCharArray();  
        while(first < last){  
            while(first < last && vowels.indexOf(array[first]) == -1){  
                first++;  
            }  
            while(first < last && vowels.indexOf(array[last]) == -1){  
                last--;  
            }  
            char temp = array[first];  
            array[first] = array[last];  
            array[last] = temp;  
            first++;  
            last--;  
        }  
        return new