题解 | #删除字符串中出现次数最少的字符#

import java.util.Scanner;
import java.util.HashMap;
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);
        String str = in.nextLine();
        char[] chars = str.toCharArray();
        HashMap<Character, Integer> map = new HashMap<>();
        for (char c : chars) {
            if (!map.containsKey(c)) {
                map.put(c, 1);
            } else {
                map.put(c, map.get(c) + 1);
            }
        }
        int min = 0;
        for (Integer value : map.values()) {
            if(min == 0) {
                min = value;
            } else if (value < min) {
                min = value;
            }
        }

        Iterator<Map.Entry<Character, Integer>> iterator = map.entrySet().iterator();
        while (iterator.hasNext()) {
            Map.Entry<Character, Integer> entry = iterator.next();
            if (entry.getValue() == min) {
                str = str.replaceAll(entry.getKey().toString(), "");
            }
        }
        System.out.println(str);
    }
}