题解 | #删除字符串中出现次数最少的字符#

import java.util.HashSet;
import java.util.Scanner;

// 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();
        String str_out = str;
        char[] chr = str.toCharArray();
        int len = 0;
        for (char index : chr) {
            if (len < str.replaceAll(String.valueOf(index), "").length()) {
                len = str.replaceAll(String.valueOf(index), "").length();
            }
        }
        for (char index : chr) {
            if (len == str.replaceAll(String.valueOf(index), "").length()) {
                str_out = str_out.replaceAll(String.valueOf(index), "");
            }
        }
        System.out.println(str_out);
    }
}