LC#345 : Reverse Vowels of a String

Question:

Given a string s, reverse only all the vowels in the string and return it. The vowels are 'a', 'e', 'i', 'o', and 'u', and they can appear in both lower and upper cases, more than once.

Example 1:
Input: s = "hello"
Output: "holle"

Example 2:
Input: s = "leetcode"
Output: "leotcede"

Constraints:

1 <= s.length <= 3 * 10⁵
s consist of printable ASCII characters.

Initial Solution:

2 pointer method is quite good here.instead of using 2 different strings, then substituting it.

    class Solution {
    public static String reverseVowels(String s) {
        String vovels = "aeiouAEIOU";
        char[] word = s.toCharArray();
        int start = 0;
        int end = word.length -1;

        for(int i=start;i<end;i++){
            if(vovels.indexOf(word[i]) != -1){
                while(end > start && vovels.indexOf(word[end])== -1){
                    end--;
                }
                char temp = word[i];
                word[i] = word[end];
                word[end] = temp;
                end--;//extra
            }
        }
        return new String(word);
    }
}