贪心策略
先定义一个自己的比较器，再排序就好了。

import java.util.Arrays;
import java.util.Comparator;

public class LowestLexicography {
    public static class MyComparator implements Comparator<String>{

        @Override
        public int compare(String a, String b) {
            return (a + b).compareTo(b + a);
        }
    }
    public static String lowestString(String[] strs){
        if(strs == null || strs.length == 0)
            return "";
        Arrays.sort(strs, new MyComparator());
        String res = "";
        for(int i = 0; i < strs.length; i++){
            res += strs[i];
        }
        return res;
    }
    public static void main(String[] args){

    }
}