题解 | HJ23#删除字符串中出现次数最少的字符#

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 scanner = new Scanner(System.in);
        String str = scanner.nextLine();
        char[] chars = str.toCharArray();
        //把这些字符以及出现的数目都存进map
        Map<Character, Integer> map = new HashMap<>();
        for (char c : chars) {
            if (map.containsKey(c)) {
                map.put(c, map.get(c) + 1);
            } else {
                map.put(c, 1);
            }
        }
        //找到map的value中最小值
        Integer min = Collections.min(map.values());
        //把map中最小数量的字符存进list
        ArrayList<Character> list = new ArrayList<>();
        for (int i = 0; i < chars.length; i++) {
            if (min.equals(map.get(chars[i]))) {
                list.add(chars[i]);
            }
        }
        //若list中不含char中某个字符 则说明数量不是最少 输出它
        for (int i = 0; i < chars.length; i++) {
            if (!list.contains(chars[i])) {
                System.out.print(chars[i]);
            }
        }


    }
}