Java Coding Test Course, Card Game

This course is for preparing for coding tests using the Java programming language. Today’s topic is ‘Card Game’. Card games are one of the very useful topics for solving algorithm problems and help students understand various data structures and algorithms.

Problem Description

The game involves finding the highest number from the opponent’s cards among the numbers written on the given deck of cards. Each player has a randomly selected card from the deck, and points are exchanged based on the numbers on those cards.

Problem

Two players, A and B, have cards. Given A’s and B’s cards, write a function to determine the win or loss of A and B according to the following rules.

• The number of cards is N, and each A and B has the same number of cards.
• The number on each card is an integer from 1 to 100.
• In each round, both players lay down one card, and the player with the higher number becomes the winner of that round.
• After all rounds are complete, the player with more victories becomes the final winner.

Input

The first line contains N (1 ≤ N ≤ 100). The second line contains the numbers of player A’s cards. The third line contains the numbers of player B’s cards.

Output

Print the number of victories for each player and who the final winner is. If the number of victories for both players is the same, print ‘Draw’.

Example Input

    5
    3 6 7 1 2
    4 5 8 1 3
    

Example Output

    A: 2, B: 3
    B
    

Solution Process

To solve this problem, the following algorithm steps are needed.

1. Receive input.
2. Compare the card numbers of A and B to determine the winner of each round.
3. Count each player’s number of victories and determine the final winner.

Getting Input

You can use the Scanner class in Java to get input. First, read the value of N and store A’s and B’s cards as arrays.

    import java.util.Scanner;

    public class CardGame {
        public static void main(String[] args) {
            Scanner scanner = new Scanner(System.in);

            int N = scanner.nextInt();
            int[] A = new int[N];
            int[] B = new int[N];

            for (int i = 0; i < N; i++) {
                A[i] = scanner.nextInt();
            }

            for (int i = 0; i < N; i++) {
                B[i] = scanner.nextInt();
            }
        }
    }
    

Counting Victories

In each round, compare the cards and increase the victory count. This comparison can be implemented with simple if-else statements.

    int scoreA = 0, scoreB = 0;

    for (int i = 0; i < N; i++) {
        if (A[i] > B[i]) {
            scoreA++;
        } else if (A[i] < B[i]) {
            scoreB++;
        }
    }
    

Determining the Final Winner

After all rounds are completed, compare the victory counts and print the result.

    System.out.println("A: " + scoreA + ", B: " + scoreB);
    
    if (scoreA > scoreB) {
        System.out.println("A");
    } else if (scoreA < scoreB) {
        System.out.println("B");
    } else {
        System.out.println("Draw");
    }
    

Full Code

    import java.util.Scanner;

    public class CardGame {
        public static void main(String[] args) {
            Scanner scanner = new Scanner(System.in);

            int N = scanner.nextInt();
            int[] A = new int[N];
            int[] B = new int[N];

            for (int i = 0; i < N; i++) {
                A[i] = scanner.nextInt();
            }

            for (int i = 0; i < N; i++) {
                B[i] = scanner.nextInt();
            }

            int scoreA = 0, scoreB = 0;

            for (int i = 0; i < N; i++) {
                if (A[i] > B[i]) {
                    scoreA++;
                } else if (A[i] < B[i]) {
                    scoreB++;
                }
            }

            System.out.println("A: " + scoreA + ", B: " + scoreB);

            if (scoreA > scoreB) {
                System.out.println("A");
            } else if (scoreA < scoreB) {
                System.out.println("B");
            } else {
                System.out.println("Draw");
            }
        }
    }
    

Conclusion

In this lecture, we solved an algorithm problem based on a card game. Algorithm problems are very helpful in understanding basic data structures and algorithms. It is important to continuously practice to develop efficient problem-solving skills. I hope you prepare well for coding tests!

References

This course was written based on the following materials:

• Java Official Documentation
• Algorithm Problem-Solving Strategies
• Programming Contest Past Questions