题解 | #提取不重复的整数#

import java.util.Scanner;

/**
 * <a href="https://www.nowcoder.com/practice/253986e66d114d378ae8de2e6c4577c1">提取不重复的数</a>
 *
 * @author hll[yellowdradra@foxmail.com]
 * @since 2024-06-13
 */
public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String num = sc.nextLine();
        System.out.println(solution(num));
    }

    public static String solution(String num) {
        boolean[] repeat = new boolean[10];
        StringBuilder sb = new StringBuilder();
        for (int i = num.toCharArray().length - 1; i >= 0; i--) {
            int index = num.charAt(i) - '0';
            if (!repeat[index]) {
                sb.append(num.charAt(i));
                repeat[index] = true;
            }
        }
        return sb.toString();
    }
}