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".

 思路：双指针首位夹逼，转成array来swap相对应的vowel，最后输出新的string

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public class Solution {
    public String reverseVowels(String s) {
        ArrayList<Character> check=new ArrayList<Character>();
        check.add('a');
        check.add('e');
        check.add('i');
        check.add('o');
        check.add('u');
        check.add('A');
        check.add('E');
        check.add('I');
        check.add('O');
        check.add('U');
        
        char[] transfer=s.toCharArray();
        
        int i=0;
        int j=transfer.length-1;
        while(i<j)
        {
            if(!check.contains(transfer[i]))
            {
                i++;
                continue;
            }
            if(!check.contains(transfer[j]))
            {
                j--;
                continue;
            }
            char temp=transfer[i];
            transfer[i]=transfer[j];
            transfer[j]=temp;
            i++;
            j--;
        }
        return new String(transfer);
}
}