HashTree红黑树搞定

import java.util.*;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        while(in.hasNextLine()){
            String s=in.nextLine();
            solve(s);
        }
        
    }
    public static void solve(String s){
        char[] str = s.toCharArray();
        Map<Character,Integer> map  = new TreeMap<>();
        for(char i:str){
            if(!map.containsKey(i)){
                map.put(i,1);
            }else{
                int value = map.get(i);
                map.put(i,value+1);
            }
        }
        for(Map.Entry<Character,Integer> entry : map.entrySet()){
            System.out.print(entry.getKey());
            System.out.print(entry.getValue());
        }
    }
}