class Solution {

    public String reverseVowels(String s) {

        char[] arr = s.toCharArray();

        int left =0;

        int right =arr.length-1;

        while(left<right)

        {

            while(!isYuanYin(s.charAt(left))&&left<right)

                left++;

            while(!isYuanYin(s.charAt(right))&&left<right)

                right--;

            swap(left,right,arr);

            left++;right--;

        }

        return new String(arr);

    }

    public boolean isYuanYin(char c)

    {

        if(c=='a'||c=='e'||c=='i'||c=='o'||c=='u')

            return true;

        if(c=='A'||c=='E'||c=='I'||c=='O'||c=='U')

            return true;

        return false;

    }

    public void swap(int i,int j,char[] arr)

    {

        char tmp = arr[i];

        arr[i] =arr[j];

        arr[j]=tmp;

    }

}