美团2015校招研发笔试题——字母排序

import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Vector;


public class MyDemo {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        System.out.println(function("abBBDSXAINiknkDKKKKJJccdDDCC"));
    }

    public static String function(String inputString){
        ArrayList<Character> arrayList=new ArrayList<>();//保存大写字母
        ArrayList<Character> arrayList2=new ArrayList<>();//保存小写字母
        StringBuffer result=new StringBuffer();
        for(int i=0;i<inputString.length();i++){
            if(inputString.charAt(i)<‘a‘){//大写字母
                arrayList.add(inputString.charAt(i));
            }else{
                arrayList2.add(inputString.charAt(i));
            }
        }
        Collections.sort(arrayList);
        Collections.sort(arrayList2);
        for(int i=0;i<arrayList2.size();i++){
            result.append(arrayList2.get(i));
        }
        for(int i=0;i<arrayList.size();i++){
            result.append(arrayList.get(i));
        }
        return result.toString();
    }
}