聪敏的随机数 java

package com.patience.interview.huawei;

import java.util.*;


public class SmartRandom {

    public static void main(String[] args) {
        final int MAX = 500;
        int[] arr = new int[MAX];
        for (int i = 0; i < MAX; i++)
            arr[i] = i + 1;
        Scanner sc = new Scanner(System.in);
        int N = sc.nextInt();
        for (int i = 0; i < N; i++){
            int num = sc.nextInt();
            int index = Arrays.binarySearch(arr,num);
            if(index < 0){
                arr[num - 1] = 0;
                continue;
            }
            arr[index] = 0;// 0占位
        }
        for (int i = 0; i < MAX; i++){
            if(arr[i] == 0)
                System.out.println(i+1);
        }
    }

    // 其他 方法
    void temp(){
        Scanner sc = new Scanner(System.in);
        //Set set = new TreeSet<>();
        List list = new ArrayList<>();
        int N = sc.nextInt();
        for (int i = 0; i < N; i++){
            int num = sc.nextInt();
            //System.out.println(num);
            //set.add(num);
            if(!list.contains(num))
                list.add(num);
        }
        Collections.sort(list);
        list.forEach(System.out::println);
    }

}