Step by Step solution about How to resolve the algorithm Sorting algorithms/Insertion sort step by step in the Kotlin programming language

The code snippet you provided is an implementation of the insertion sort algorithm in Kotlin. Insertion sort is a relatively simple sorting algorithm that works by iterating through the array from left to right, and for each element, inserting it into its correct position in the sorted portion of the array.

The insertionSort function takes an array of integers as input and sorts it in ascending order. The algorithm works as follows:

1. For each element in the array, starting with the second element, do the following:

   • Save the current element in a variable called value.
   • Set a variable called subIndex to the index of the previous element in the array (index - 1).
   • While subIndex is greater than or equal to 0 and the element at index subIndex in the array is greater than value, do the following:
     • Swap the element at index subIndex + 1 in the array with the element at index subIndex.
     • Decrement subIndex by 1.
   • Insert the value into the array at index subIndex + 1.

2. Repeat step 1 for each element in the array.

The time complexity of insertion sort is O(n^2), where n is the number of elements in the array. This means that the algorithm takes a relatively long time to sort large arrays. However, insertion sort is relatively simple to implement and can be efficient for small arrays.

The main function in the code snippet you provided tests the insertionSort function by sorting an array of integers. The unsorted array is printed to the console, the insertionSort function is called to sort the array, and the sorted array is printed to the console.

fun insertionSort(array: IntArray) {
    for (index in 1 until array.size) {
        val value = array[index]
        var subIndex = index - 1
        while (subIndex >= 0 && array[subIndex] > value) {
            array[subIndex + 1] = array[subIndex]
            subIndex--
        }
        array[subIndex + 1] = value
    }
}

fun main(args: Array<String>) {
    val numbers = intArrayOf(5, 2, 3, 17, 12, 1, 8, 3, 4, 9, 7)

    fun printArray(message: String, array: IntArray) = with(array) {
        print("$message [")
        forEachIndexed { index, number ->
            print(if (index == lastIndex) number else "$number, ")
        }
        println("]")
    }

    printArray("Unsorted:", numbers)
    insertionSort(numbers)
    printArray("Sorted:", numbers)
}