Leecode 345 翻转字符串中的元音字母-双指针法

class Solution {
    public String reverseVowels(String s) {
        //1.转换为char数组
        char[] a = s.toCharArray();
        //2.把原因字母存进HashMap,用来判断是不是元音字母
        Map<Character,Integer> map = new HashMap<>();
        char[] words = {'a','o','e','i','u','A','O','E','I','U'};
        for(int i=0;i<words.length;i++){
            map.put(words[i],1);
        }
        //3.双指针向中间逼近,遇到元音字母互换位置,直到两指针重合或交叉
        int i=0;
        int j=a.length-1;
    while(i<j){
        char word1=a[i];
        char word2=a[j];
        if(!map.containsKey(word1)){
            i++;
        }
        if(!map.containsKey(word2)){
            j--;
        }
        if(map.containsKey(word1)&&map.containsKey(word2)){//交换位置
            char temp = word1;
            a[i]=word2;
            a[j]=temp;
            i++;
            j--;
        }
    }
    StringBuilder builder = new StringBuilder();
    for(int k=0;k<a.length;k++){
        builder.append(a[k]);
    }
    String result = String.valueOf(builder);
    return result;
    }
}```