JavaScript Coding Test Course, Card Game

1. Introduction

Coding tests are an important part of the software developer hiring process, as they assess problem-solving abilities in algorithms. In this course, we will take a detailed look at solving card game-related problems using JavaScript. Card games are a familiar type of game for many people and provide an opportunity to develop basic algorithmic thinking. JavaScript is primarily used in web-based environments, so many jobs require proficiency in JavaScript.

2. Problem Description

Below is an algorithm problem related to card games.

Problem: Organizing Cards

You are playing a card game with N cards. Each card has a unique number from 1 to N. Your goal is to sort the cards in order from the smallest number to the largest number. However, there are many cards, making it difficult to do this manually.

Write a function to sort the given array of cards. The function should take the length of the array as input and output the sorted array.

Example:

• Input: [3, 1, 4, 2]
• Output: [1, 2, 3, 4]

3. Approach to the Problem

To solve this problem, we will follow these steps:

1. Analyze the elements of the input array to determine which sorting algorithm is most suitable.
2. Implement the selected sorting algorithm in JavaScript code.
3. Validate the obtained results through test cases.

4. Code Implementation

There are various sorting algorithms that can be used in JavaScript. Commonly used sorting algorithms include:

• Bubble Sort
• Selection Sort
• Insertion Sort
• Quick Sort
• Merge Sort
• JavaScript Built-in Sort Method (sort)

This time, we will use the built-in method sort() of JavaScript to solve the problem.

function sortCards(cards) {
            return cards.sort((a, b) => a - b);
        }
        
        // Test
        const unsortedCards = [3, 1, 4, 2];
        const sortedCards = sortCards(unsortedCards);
        console.log(sortedCards);  // [1, 2, 3, 4]
        

5. Code Explanation

The sortCards function implemented above sorts the given array of cards. This function includes the following steps:

1. cards.sort((a, b) => a - b): The sort() method is used to sort the array of cards. This method performs string sorting by default, so a callback function is provided for numeric sorting.
2. The callback function compares the two arguments a and b to determine their order based on the result. If the value of a - b is negative, a is considered to come before b.
3. Returns the sorted array.

6. Test Cases

Let’s run various test cases to validate the accuracy of the function.

function testSortCards() {
            console.assert(JSON.stringify(sortCards([3, 1, 4, 2])) === JSON.stringify([1, 2, 3, 4]), "Test Case 1 Failed");
            console.assert(JSON.stringify(sortCards([10, 5, 3, 8])) === JSON.stringify([3, 5, 8, 10]), "Test Case 2 Failed");
            console.assert(JSON.stringify(sortCards([-1, 0, 1])) === JSON.stringify([-1, 0, 1]), "Test Case 3 Failed");
            console.assert(JSON.stringify(sortCards([4, 4, 4])) === JSON.stringify([4, 4, 4]), "Test Case 4 Failed");
            console.log("All test cases pass");
        }
        
        testSortCards();

The above testSortCards function contains tests for various scenarios and outputs which test case failed if any test fails.

7. Performance Considerations

The JavaScript sort() method has an average time complexity of O(n log n). Therefore, it performs excellently even for large data sets. However, if you use a sorting algorithm that you implemented yourself, the performance may vary depending on the implementation. In particular, inefficient algorithms like bubble sort or selection sort can lead to performance degradation when processing large amounts of data, so it is advisable to choose efficient algorithms.

8. Conclusion

In this course, we implemented a solution to a card game problem using JavaScript and looked closely at the approach to the problem and the code. We confirmed that the built-in sorting method sort() in JavaScript can simplify solving this problem. Algorithm problems can be a challenging endeavor, but attempting various methods and accumulating experience is essential. I encourage you to utilize various algorithms and data in solving problems in the future.