【102】字符统计

import java.util.*;
import java.util.Map.Entry;

public class Main {

    public static void getCount(String input){
        if(input == null || input.length() <= 0){
            return;
        }
        char[] arrs = input.toCharArray();
        //按字符的ASCII码排序，由小到大
        Comparator<Character> com1 = new Comparator<Character>(){
            @Override
            public int compare(Character o1, Character o2) {
                return o1.compareTo(o2);
            }
        };
        TreeMap<Character, Integer> map = new TreeMap<>(com1);
        for(int i = 0; i < arrs.length; i++){
            char c  = arrs[i];
            if(c == ‘ ‘
                    || c >= ‘0‘ && c <= ‘9‘ 
                    || c >= ‘a‘ && c <= ‘z‘
                    || c >= ‘A‘ && c <= ‘Z‘){
                map.put(c, (map.get(c) == null ? 0 : map.get(c) ) + 1);
            }
        }
        
        ArrayList<Map.Entry<Character, Integer>> list = new ArrayList<>(map.entrySet());
        //按字符出现的次数排序，由大到小
        Comparator<Map.Entry<Character, Integer>> com2 = new Comparator<Map.Entry<Character, Integer>>(){
            @Override
            public int compare(Entry<Character, Integer> o1, Entry<Character, Integer> o2) {
                return o2.getValue().compareTo(o1.getValue());
            }
        };
        Collections.sort(list, com2);
        for(int i = 0; i < list.size(); i++){
            System.out.print(list.get(i).getKey());
        }
        System.out.println();
    }
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        while(sc.hasNext()){
            String input = sc.next();
            getCount(input);
        }
        
    }
}