今日头条编程题

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner cin = new Scanner(System.in);
        int m = cin.nextInt();
        int[] a = new int[m];
        for (int i = 0; i < m; i++) {
            a[i] = cin.nextInt();
        }
        int n = cin.nextInt();
        int[] b = new int[n];
        for (int i = 0; i < n; i++) {
            b[i] = cin.nextInt();
        }
        helper(a, b);
    }
    
    public static void helper(int[] a, int[] b) {
        int m = a.length;
        int n = b.length;
        for (int j = 0; j < n; j++) {
            for (int i = 0; i < m; i++) {
                if (a[i] == b[j]) 
                    System.out.println(b[j]);
            }
        }
    }
}

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

public class Main {
    public static void main(String[] args) {
        Scanner cin = new Scanner(System.in);
        
        int m = cin.nextInt();
        int[] a = new int[m];
        for (int i = 0; i < m; i++) {
            a[i] = cin.nextInt();
        }
        
        int n = cin.nextInt();
        int[] b = new int[n];
        for (int i = 0; i < n; i++) {
            b[i] = cin.nextInt();
        }
        
        //将a中的数据添加到Hashset中，利用hashset的不重复性来比较b数组中的数据；
        Set<Integer> set = new HashSet<Integer>();
        String rst = "";
        for (int i = 0; i < m; i++) {
            set.add(a[i]);
        }
        
        for (int j = 0; j < n; j++) {
            if (!set.add(b[j])) {
                rst += b[j] + " ";
            }
        }
        
        System.out.println(rst.trim());
    }
}