Reverse Vowels Of A String

Reverse Vowels Of A String 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".

Reverse Vowels Of A String Solution

public class ReverseVowelsOfAString {
    public String reverseVowels(String s) {
        if(s == null || s.length() == 0) {
            return s;
        }

        String vowels = "aeiouAEIOU";

        char[] chars = s.toCharArray();

        int start = 0;
        int end = s.length() - 1;

        while(start < end) {
            while(start < end && !vowels.contains(chars[start] + "")) {
                start++;
            }

            while(start < end && !vowels.contains(chars[end] + "")) {
                end--;
            }

            char temp = chars[start];
            chars[start] = chars[end];
            chars[end] = temp;

            start++;
            end--;
        }

        return new String(chars);
    }
}

Last modified October 4, 2020