package leetCode_345;

import java.util.Arrays;

import java.util.HashSet;

/**

* @author dimdark

* @date 2017-09-12

* @time 9:15 PM

*/

public class Solution {

private HashSet<Character> createVowelSet() {

HashSet<Character> vowels = new HashSet<Character>();

vowels.add('a');

vowels.add('e');

vowels.add('i');

vowels.add('o');

vowels.add('u');

return vowels;

}

public String reverseVowels(String s) {

if (s == null) return null;

HashSet<Character> vowels = createVowelSet();

char[] chars = s.toCharArray();

int i = 0, j = chars.length - 1;

while (i < j) {

while (i < j && !vowels.contains(Character.toLowerCase(chars[i]))) {

i++;

}

while (i < j && !vowels.contains(Character.toLowerCase(chars[j]))) {

j--;

}

if (i >= j) break;

char tmpChar = chars[i];

chars[i] = chars[j];

chars[j] = tmpChar;

i++; j--;

}

return String.valueOf(chars);

}

}