题解 | #最大子序列#

import java.util.Arrays;
import java.util.Scanner;

/**
 * BD12 最大子序列
 * @Author zhuyq
 * @Date 2021-09-17
 */
public class Main {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        System.out.println(f(in.nextLine(), ""));
    }

    //获取字符串字典序最大的子串
    public static String f(String s, String t){
        //获取字符串最大字典序的字符
        char[] chars = s.toCharArray();
        Arrays.sort(chars);
        char maxChar = chars[chars.length-1];
        int pos = s.indexOf(String.valueOf(maxChar));
        t += maxChar;

        if(pos==s.length()-1){
            return t;
        }
        else{
            s = s.substring(pos+1, s.length());
            return f(s, t);
        }
    }






}