题解 | #删除字符串中出现次数最少的字符#

import java.util.Scanner;
import java.util.LinkedHashMap;
import java.util.Set;

// 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);
        // 注意 hasNext 和 hasNextLine 的区别
        while (in.hasNextLine()) { // 注意 while 处理多个 case
            String input = in.nextLine();

            LinkedHashMap<Character, Integer> linkhashmap = new
            LinkedHashMap<Character, Integer>();

            for (int i = 0; i < input.length(); i++) {
                linkhashmap.put(input.charAt(i), linkhashmap.getOrDefault(input.charAt(i),
                                0) + 1);
            }

            Set<Character> tempSet = linkhashmap.keySet();
            //System.out.println(linkhashmap);
            //System.out.println(tempSet);


            int minNum = 100;
            for (Character a : tempSet) {
                if (linkhashmap.get(a) < minNum) {
                    minNum = linkhashmap.get(a);
                }
            }

            //System.out.println(minNum);


            for (Character a : tempSet) {
                if (linkhashmap.get(a) == minNum) {
                    String s1 = a +"";
                    //System.out.println(s1);

                    input = input.replaceAll(s1,"");
                }
            }

            System.out.println(input);
        }
    }
}