大哥大姐求解啊T_T?美团两题为啥都为0，感觉思路都没错啊

//被7整除
import java.util.HashSet;
import java.util.Scanner;
import java.util.Set;

public class Main{

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner in = new Scanner(System.in);
		while(true){
			int num = Integer.parseInt(in.nextLine());
			String[] input = in.nextLine().split(" ");
			Set<Integer> set = new HashSet<>();
			boolean[][] flag = new boolean[num][num];
			for(int i =0;i<num;i++){
				for(int j=0;j<num;j++){
					flag[i][j] = false;
				}
			}
			for(int i =0;i<input.length;i++){
				for(int j = 0;j<input.length;j++){
					if(i != j && !flag[i][j]){
						int a1 = Integer.parseInt(input[i]+input[j]);
						int a2 = Integer.parseInt(input[j]+input[i]);
						flag[i][j] = true;
						flag[j][i] = true;
						if(a1%7==0){
							set.add(a1);
						}
						if(a2%7==0){
							set.add(a2);
						}
					}
				}
			}
			System.out.println(set.size());
		}
	}
}


//灯泡问题
import java.util.Scanner;

public class Main{

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner in = new Scanner(System.in);
		while (true) {
			int num = in.nextInt();
			int[] arr = new int[num];
			for (int i = 0; i < num; i++) {
				arr[i] = in.nextInt();
			}
			if (arr[num - 1] == 1) {
				System.out.println("Alice");
			} else {
				System.out.println("Bob");
			}

		}

	}
}
求解啊啊啊啊啊！！T_T为啥一点都不能通过。。。