Question

Using Java Eclipse with comments:

The main purpose of this programming assignment is for students to have a deep understanding of how to implement Heapsort algorithm.

1.1 Details

l Implement Heapsort algorithm; run the program on two different manners:

1)      Ask the user to select a number (the array size x); also ask the user to provide all x elements in the user interface; display this user-supplied array BOTH before AND after sorting.

2)      Ask the user to select an array from a list of pre-defined arrays (generated by your program); display this pre-defined array BOTH before AND after sorting.

3)      The interface will keep waiting for the user selection (between the above two manners) until the user chooses to exit.

Answer 1

Hi friend, Question is long.

I have answered Part I

import java.util.Arrays;
import java.util.Scanner;

//Java program for implementation of Heap Sort
public class HeapSort
{
   public static void sort(int arr[])
   {
       int n = arr.length;

       // Build heap (rearrange array)
       for (int i = n / 2 - 1; i >= 0; i--)
           heapify(arr, n, i);

       // One by one extract an element from heap
       for (int i=n-1; i>=0; i--)
       {
           // Move current root to end
           int temp = arr[0];
           arr[0] = arr[i];
           arr[i] = temp;

           // call max heapify on the reduced heap
           heapify(arr, i, 0);
       }
   }

   // To heapify a subtree rooted with node i which is
   // an index in arr[]. n is size of heap
   static void heapify(int arr[], int n, int i)
   {
       int largest = i; // Initialize largest as root
       int l = 2*i + 1; // left = 2*i + 1
       int r = 2*i + 2; // right = 2*i + 2

       // If left child is larger than root
       if (l < n && arr[l] > arr[largest])
           largest = l;

       // If right child is larger than largest so far
       if (r < n && arr[r] > arr[largest])
           largest = r;

       // If largest is not root
       if (largest != i)
       {
           int swap = arr[i];
           arr[i] = arr[largest];
           arr[largest] = swap;

           // Recursively heapify the affected sub-tree
           heapify(arr, n, largest);
       }
   }

   /* A utility function to print array of size n */
   static void printArray(int arr[])
   {
       int n = arr.length;
       for (int i=0; i<n; ++i)
           System.out.print(arr[i]+" ");
       System.out.println();
   }

   // Driver program
   public static void main(String args[])
   {
       Scanner sc = new Scanner(System.in);

       System.out.print("How many integers want to enter: ");
       int n = sc.nextInt();

       int arr[] = new int[n];

       System.out.println("Enter "+n+" numbers: ");

       for(int i=0; i<n; i++)
           arr[i] = sc.nextInt();

       System.out.println("Array before sorting: ");
       System.out.println(Arrays.toString(arr));
       sort(arr);

       System.out.println("Array after sorting: ");
       System.out.println(Arrays.toString(arr));
   }
}

Problems @ Javadoc DeclarationSearchoProgressRemote Systems TeStNG «terminated» Heapsort [Java Application] /Library/Java/JavaVirtualMachinesidk18.0-102. dk/Contents/Home/bin/java (06-Apr-2018, 12:13:18 How many integers want to enter: 5 Enter 5 numbers: 45 21 34 89 54 Array before sorting: [45, 21, 34, 89, 54] Array after sorting [21, 34, 45, 54, 89]

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