题解 | #字符统计#

import java.util.Scanner;
import java.util.*;
import java.util.stream.Collectors;

// 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 scanner = new Scanner(System.in);
        String str = scanner.nextLine();
        countStr(str);
    }

    public static void countStr(String input) {
        Map<Character, Integer> map = new HashMap<>();
        char[] chars = input.toCharArray();
        for (int i = 0; i < chars.length; i++) {
            char c = chars[i];
            if (map.containsKey(c)) {
                map.put(c, map.get(c) + 1);
            } else {
                map.put(c, 1);
            }
        }

        mapSort(map);

    }

    public static void mapSort(Map<Character, Integer> map) {
        List<StrCountSortVO> list = new ArrayList<>();
        map.forEach((k, v)-> {
            StrCountSortVO strCountSortVO = new StrCountSortVO(k, v);
            list.add(strCountSortVO);
        });

        List<StrCountSortVO> result =  list.stream().sorted(Comparator.comparing(
                                           StrCountSortVO::getCount).reversed()
                                       .thenComparing(StrCountSortVO::getStr)
                                                           ).collect(Collectors.toList());
        for (StrCountSortVO strCountSortVO : result) {
            System.out.print(strCountSortVO.str);
        }
    }
}


class StrCountSortVO {
    public  Character str;
    public Integer count;
    StrCountSortVO( Character str, Integer count) {
        this.str = str;
        this.count = count;
    }

    public Character getStr() {
        return str;
    }

    public Integer getCount() {
        return count;
    }
}