kotlin coding test course, finding the minimum value 2

Hello! In this post, we will discuss the topic “Finding Minimum Value 2” as part of the Kotlin coding test course. Among various algorithm problems, finding the minimum value is a common problem with various variations. In this article, we will define the problem and explain the Kotlin algorithm to solve it step by step.

Problem Definition

Let’s solve the following problem:

Problem: Given an integer array nums, write a program that finds the smallest element in the array. The size of the array is assumed to be at least 1, and the integer values are assumed to range from -10⁹ to 10⁹. If the array is empty or contains values that differ from the specification, it should throw an IllegalArgumentException.

Problem Analysis

To solve the problem, we need to consider an algorithm that finds the smallest number in the array. The basic idea to find the minimum is to traverse the array once and update the minimum value by comparing each element. The method of traversing the array once has a time complexity of O(n), which is very efficient. There are various algorithms besides this method, but here we will use the most basic approach.

Algorithm Design

The algorithm consists of the following steps:

1. Exception Handling: Throw an IllegalArgumentException if the array is empty.
2. Initialize Minimum Value: Initialize the minimum value with the first element of the array.
3. Traverse Array: Check each element of the array and update the minimum value if a value less than the current minimum is found.
4. Return Minimum Value: Finally, return the found minimum value.

Kotlin Code Implementation

Now let’s look at the code that implements the above algorithm:

fun findMinimum(nums: IntArray): Int {
    // 1. Check if the array is empty
    if (nums.isEmpty()) {
        throw IllegalArgumentException("The array is empty.")
    }

    // 2. Initialize the minimum value
    var minValue = nums[0]

    // 3. Traverse the array
    for (num in nums) {
        if (num < minValue) {
            minValue = num
        }
    }

    // 4. Return the minimum value
    return minValue
}

Code Explanation

Looking at the above code:

• fun findMinimum(nums: IntArray): Int: This function takes an integer array as a parameter and returns the minimum value.
• if (nums.isEmpty()): If the array is empty, it throws an exception.
• var minValue = nums[0]: Initializes the minimum value with the first element of the array.
• for (num in nums): Traverses all elements of the array
• if (num < minValue): If the current element is less than the minimum value, it updates the minimum value.
• Finally, it returns the minimum value.

Test Cases

Now let’s look at some test cases to test the implemented function:

fun main() {
    val testCases = arrayOf(
        intArrayOf(3, 5, 1, 8, 2),
        intArrayOf(-1, -3, -5, -2),
        intArrayOf(10),
        intArrayOf(0, 1, 0, -1, -2, 2, 1),
        intArrayOf()
    )

    for (testCase in testCases) {
        try {
            println("Test Case: ${testCase.joinToString(", ")} -> Minimum Value: ${findMinimum(testCase)}")
        } catch (e: IllegalArgumentException) {
            println("Test Case: ${testCase.joinToString(", ")} -> Exception Occurred: ${e.message}")
        }
    }
}

Test Results

The results of running the above test cases are as follows:

• Test Case: 3, 5, 1, 8, 2 -> Minimum Value: 1
• Test Case: -1, -3, -5, -2 -> Minimum Value: -5
• Test Case: 10 -> Minimum Value: 10
• Test Case: 0, 1, 0, -1, -2, 2, 1 -> Minimum Value: -2
• Test Case: (Empty Array) -> Exception Occurred: The array is empty.

Conclusion

In this lecture, we reviewed the process of solving the minimum value finding problem using Kotlin. Although it is a basic algorithm to find the smallest value in an array, it allows us to solve the problem efficiently and simply by traversing the array and checking conditions. Such problems are frequently encountered in coding tests, making them very useful for practicing basic algorithms.

I hope this lecture has been helpful, and that it aids you in enhancing your algorithm skills! If you have any additional questions or feedback, feel free to leave a comment.

References

• Kotlin Official Documentation
• LeetCode – Algorithm Problem Practice Platform
• GeeksforGeeks – Programming Problems and Solutions

I hope you continue to learn various problems and algorithms. Thank you!