求最小合并字符串 ---贪心算法

public class FindMinGroupInArrs {
    public static class myComparor implements Comparator<String>{
        @Override
        public int compare(String s1, String s2) {
            return (s1+s2).compareTo(s2+s1); //s1.compareTo(s2+s1)  正数代表前面大
        }
    }
    public static String returnMinSringGroup(String[] strs){
        if (strs==null){
            return "";
        }
        Arrays.sort(strs,new myComparor()); //Arrays.sort传入自己比较器后,正数代表交换,负数代表不交换
        String res="";
        for(int i=0;i<strs.length;i++){
            res+=strs[i];
        }
        return res;
    }

}