JavaScript Coding Test Course, Why is Debugging Important?

Coding tests are one of the important ways to assess the capabilities of a software engineer. In particular, JavaScript is one of the most widely used languages in web development and is often used to solve various algorithmic problems. In this post, we will present an algorithm problem that can be solved with JavaScript and emphasize the importance of debugging in the process of finding a solution.

Problem Description

Problem: Two Sum

The problem is to find two numbers in a given array such that their sum equals a specific value (target), and return the indices of those two numbers. It is assumed that there is always exactly one solution.

Function Signature

function twoSum(nums: number[], target: number): number[] {
        // Your code here
    }

Example Input and Output

  • Input: nums = [2, 7, 11, 15], target = 9
  • Output: [0, 1]
  • Input: nums = [3, 2, 4], target = 6
  • Output: [1, 2]
  • Input: nums = [3, 3], target = 6
  • Output: [0, 1]

Solution

To solve this problem, we need to iterate through the array and check if the complement of each element exists in the array. However, this method has a worst-case time complexity of O(n^2), which is inefficient. Therefore, we can use a hashmap (or object) to achieve a more efficient O(n) time complexity.

Step 1: Problem Analysis

Given an array [2, 7, 11, 15] and a target of 9, we can solve it through the following steps:

  • Look at 2 and check if 7 (9 – 2) exists in the hashmap.
  • Since 7 is not there, add 2 to the hashmap.
  • Look at 7 and check if 2 (9 – 7) exists in the hashmap.
  • Since 2 exists, we return the indices [0, 1].

Step 2: Write the Code

function twoSum(nums, target) {
        const map = new Map();
        
        for (let i = 0; i < nums.length; i++) {
            const complement = target - nums[i];
            
            if (map.has(complement)) {
                return [map.get(complement), i];
            }
            map.set(nums[i], i);
        }
        
        throw new Error("No two sum solution");
    }

Step 3: Debugging Process

After writing the code, it is essential to go through a debugging process. Here are some things to pay attention to during code debugging:

  • Error handling: Ensure that appropriate error messages are returned if the input array is empty or if no two numbers can be found.
  • Variable checking: Print intermediate results to the console to ensure that the map object is functioning correctly.
  • Performance review: Especially test performance with larger input data.

Importance of Debugging

Debugging is one of the key processes in programming. Through debugging, we can identify and fix issues in the code, allowing us to develop higher-quality software. Debugging is particularly important for the following reasons:

  1. Improving problem-solving skills: The debugging process provides an opportunity to learn how to analyze and solve various problems.
  2. Improving code readability: During the process of finding and fixing issues, we learn methods to enhance code readability.
  3. Improving project quality: The process of identifying and fixing errors in advance enhances the quality of the final product.
  4. Foundation for team collaboration: Debugging experiences enhance collaboration among team members and help in understanding each other’s code.

Conclusion

In this posting, we emphasized the importance of JavaScript coding tests and the necessity of debugging through a simple algorithm problem. Not only is it crucial to solve problems, but finding and fixing errors that may occur in the process is essential for growing as a better developer. We will return with more diverse topics in the future.