题解 | #提取不重复的整数#

使用boolean数组储存状态更快

import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int num = in.nextInt();
        boolean[] used = new boolean[10];
        StringBuilder sb = new StringBuilder();
        while (num != 0) {
            int a = num % 10;
            if (used[a] == false) {
                sb.append(a);
                used[a] = true;
            }
            num /= 10;
        }
        System.out.println(sb.toString());
    }
}