Solution for Logic 1 (https://youtu.be/PQIR2E-xva8)

MagicTrick.java

import java.util.*;

public class MagicTrick {

  static Scanner sc = new Scanner(System.in);

  public static void main(String[] args) {
    
    int t = Integer.valueOf(sc.nextLine());

    for (int i = 1; i <= t; i++) {

      // Handling input
      int guess1 = Integer.valueOf(sc.nextLine());
      int[][] cards1 = readCards();
      int guess2 = Integer.valueOf(sc.nextLine());
      int[][] cards2 = readCards();

      // Find common cards
      int[] pickedCards1 = cards1[guess1 - 1];
      int[] pickedCards2 = cards2[guess2 - 1];

      int nCommonCards = 0;
      int commonCard = -1;
      for (int card1 : pickedCards1) {

        for (int card2 : pickedCards2) {

          if (card1 == card2) {
            nCommonCards++;
            commonCard = card1;
          }

        }

      }

      // Print the result

      String result;

      if (nCommonCards == 0)
        result = "Volunteer cheated!";

      else if (nCommonCards == 1)
        result = String.valueOf(commonCard);

      else
        result = "Bad magician!";

      System.out.printf("Case #%d: %s\n", i, result);

    }

  }

  public static int[][] readCards() {

    int[][] cards = new int[4][4];

    for (int row = 0; row < 4; row++) {

      String[] line = sc.nextLine().split(" ");
      for (int col = 0; col < 4; col++) {
        cards[row][col] = Integer.valueOf(line[col]);
      }

    }

    return cards;

  }

}