1859. Sorting the Sentence

class Solution {
    public String sortSentence(String s) {
        String []ans=s.split(" ");
        String []res=new String[ans.length];
        for(int i=0;i<ans.length;i++){
            String a=ans[i];
            int n=a.length();
            int x=(a.charAt(n-1)-'0');
            res[x-1]=a.substring(0,n-1);
        }
        StringBuilder sort=new StringBuilder();
        for(String r:res){
            sort.append(r);
            sort.append(" ");
        }
        return sort.toString().trim();
    }
}