Java Coding Test Course, Preparing for Resignation

The coding test is one of the essential recruitment processes conducted by many companies. Especially in IT and software-related positions, algorithm problem-solving skills serve as a crucial evaluation criterion. In this course, we will select an algorithm problem that will help prepare for coding tests using the Java programming language and explain the process of solving it in detail.

Problem Statement: Finding the Minimum Difference Between Two Integers

Let’s solve the following problem.

Problem Description: Given an integer array nums, find the minimum difference between two integers. Note that the two numbers in the array must be chosen differently.

Input: An integer array nums

Output: The minimum difference between the two numbers

Example

Input: [4, 1, 8, 7]
Output: 1  (Detailed explanation: The difference between 8 and 7 is minimum, so the result is 1)

Approach to Problem Solving

To solve this problem, we will follow these steps.

  1. Sort the array. This makes it easier to find the two closest numbers.
  2. Calculate the differences in the sorted array and find the minimum value.

Step 1: Sorting the Array

Sort the given array using Java’s built-in sort method.

Step 2: Calculating the Difference

Now, we will calculate the difference between adjacent numbers in the sorted array to find the minimum value. This can be implemented simply using a loop.

Java Code Implementation

Now, let’s write the Java code according to the approach mentioned above.

import java.util.Arrays;

public class MinDifference {
    public static int findMinDifference(int[] nums) {
        // Sort the array
        Arrays.sort(nums);
        
        int minDiff = Integer.MAX_VALUE; // Initialize to maximum value
        
        // Compare the differences of adjacent numbers
        for (int i = 0; i < nums.length - 1; i++) {
            int diff = nums[i + 1] - nums[i];
            if (diff < minDiff) {
                minDiff = diff; // Update minimum value
            }
        }
        
        return minDiff;
    }

    public static void main(String[] args) {
        int[] nums = {4, 1, 8, 7}; // Test array
        System.out.println("Minimum difference between the two integers: " + findMinDifference(nums));
    }
}

Code Explanation

The above code is implemented to perform the following functions.

  • Sort the Array: Sorts the input array using Arrays.sort(nums);.
  • Calculate Minimum Difference: Uses a for loop to calculate the difference between adjacent elements.
  • Output the Result: Outputs the minimum value using System.out.println().

Time Complexity

The time complexity of this algorithm is O(n log n). This is related to the amount of computation needed to sort the array. The subsequent part of finding the minimum value is O(n).

Conclusion

In this problem, we explored the process of solving a simple algorithm problem using Java. In the process of preparing for coding tests, it is important to gain experience by solving various problems and finding efficient solutions for each one. We plan to introduce more algorithm problems and solutions in the future, and wish for your algorithm problem-solving skills to improve through consistent practice.

Additional Learning Resources

We recommend the following resources for coding tests:

  • Books: “Introduction to Algorithms” by Thomas H. Cormen
  • Online Courses: Coursera, Udacity, LeetCode Premium
  • Practice Platforms: HackerRank, Codewars, AtCoder

Additionally, please continue to practice by finding solutions to various problems.