题解 | #删除字符串中出现次数最少的字符#

import javax.xml.crypto.dsig.keyinfo.RetrievalMethod;
import java.util.*;
import java.util.function.Consumer;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String s = sc.next();
        StringBuilder sb = new StringBuilder(s);
        HashMap<Character, Integer> map = new HashMap<>();
        for (int i = 0; i < s.length(); i++) {
            char c = s.charAt(i);
            Integer count = map.get(c);
            if (count == null) {
                count = 0;
            }
            map.put(c, count + 1);
        }
        int min = Integer.MAX_VALUE;
        for (Map.Entry<Character, Integer> entry : map.entrySet()) {
            Character key = entry.getKey();
            Integer value = entry.getValue();
            if (value < min) {
                min = value;
            }
        }
        for (int i = 0; i < sb.length(); i++) {
            char c = sb.charAt(i);
            if (min == map.get(c)) sb.deleteCharAt(i--);
        }
        System.out.println(sb);
    }
}