题解 | #删除字符串中出现次数最少的字符#

import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Scanner;
import java.util.Set;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {

    private static char c = ' ';
    private static int count = 99;
    private static Map<Character, Integer> map = new HashMap<>();

    public static void main(String[] args) {

        String s = "";
        Scanner in = new Scanner(System.in);
        // 注意 hasNext 和 hasNextLine 的区别
        while (in.hasNext()) { // 注意 while 处理多个 case
            s = in.next();
        }

        result(s);
    }


    private static void result(String s) {

        
        int len = s.length();
        for (int i = 0;i<len; i++) {
            char c = s.charAt(i);
            map.put(c, map.getOrDefault(c, 0)+1);
        }

        map.forEach((k,v) -> {
            if(v < count){
                count = v;
                c = k.charValue();
            }
        });

        Set<Character> set = new HashSet<>();
        map.forEach((k,v) -> {
            if(v == count){
                count = v;
                c = k.charValue();
                set.add(k);
            }
        });

        for(Character c: set){
            s = s.replaceAll(c+"", "");
        }
        
        System.out.print(s);
    }

}

感觉写的有点复杂