题解 | #字符统计#

方法很low，希望大家给出修改方向

import java.util.*;
public class Main{
    public static void main(String [] args){
        getCharacterSort();
    }
    public static void getCharacterSort(){
        Scanner scan = new Scanner(System.in);
        while(scan.hasNext()){
            String input = scan.nextLine();
            Map<String, Integer> map = new HashMap<>();
            int len = input.length();
            for(int i = 0 ; i < len; i++){
                String temp = input.charAt(i) + "";
                if(map.containsKey(temp)){
                    map.put(temp, map.get(temp) + 1);
                } else{
                    map.put(temp, 1);
                }
            }
            // 针对map的value进行排序
            List<Integer> list = new ArrayList(map.values());
            Integer[] val = list.toArray(new Integer[list.size()]);
            Arrays.sort(val);
            for(int i = val.length-1; i >= 0; i--){
                List<String> temp = new ArrayList<>();
                for(String key: map.keySet()){
                    if(val[i] == map.get(key)){
                        temp.add(key);
                    }
                }
                int size = temp.size();
                i = i - size + 1;
                if(size > 1){
                    String [] keys = temp.toArray(new String[size]);
                    Arrays.sort(keys);
                    for(int j = 0; j < keys.length; j++){
                        System.out.print(keys[j]);
                    }
                } else {
                    System.out.print(temp.get(0));
                }
            }
            System.out.println();
        }
    }
}