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import java.util.Scanner;

/**

* Heap Sort Algorithm. Implements MinHeap

*

*/

public class HeapSort {

/**

* array to store heap.

*/

private int[] heap;

/**

* size of heap.

*/

private int size;

/**

* Constructor.

*

* @param heap

* array of unordered integers

*/

public HeapSort(int[] heap) {

this.setHeap(heap);

this.setSize(heap.length);

}

/**

* Sets this.size with {@code length).

*

* @param length

* integer length of heap

*/

private void setSize(int length) {

this.size = length;

}

/**

* Sets Heap with {@code heap}.

*

* @param heap

* array of unordered elements

*/

private void setHeap(int[] heap) {

this.heap = heap;

}

/**

* Swaps index of {@code first} with {@code second}.

*

* @param first

* index to swap {@code second} with

* @param second

* index to swap {@code first} with

*/

private void swap(int first, int second) {

int temp = this.heap[first];

this.heap[first] = this.heap[second];

this.heap[second] = temp;

}

/**

* Heapifies subtree from {@code top} as root to {@code last} as last child.

*

* @param rootIndex

* index of root

* @param lastChild

* index of last child

*/

private void heapSubtree(int rootIndex, int lastChild) {

int leftIndex = rootIndex * 2 + 1;

int rightIndex = rootIndex * 2 + 2;

int root = this.heap[rootIndex];

if (rightIndex <= lastChild) { // if has right and left children

int left = this.heap[leftIndex];

int right = this.heap[rightIndex];

if (left < right && left < root) {

this.swap(leftIndex, rootIndex);

this.heapSubtree(leftIndex, lastChild);

} else if (right < root) {

this.swap(rightIndex, rootIndex);

this.heapSubtree(rightIndex, lastChild);

}

} else if (leftIndex <= lastChild) { // if no right child, but has left child

int left = this.heap[leftIndex];

if (left < root) {

this.swap(leftIndex, rootIndex);

this.heapSubtree(leftIndex, lastChild);

}

}

}

/**

* Makes heap with {@code root} as root.

*

* @param root

* index of root of heap

*/

private void makeMinHeap(int root) {

int leftIndex = root * 2 + 1;

int rightIndex = root * 2 + 2;

boolean hasLeftChild = leftIndex < this.heap.length;

boolean hasRightChild = rightIndex < this.heap.length;

if (hasRightChild) { //if has left and right

this.makeMinHeap(leftIndex);

this.makeMinHeap(rightIndex);

this.heapSubtree(root, this.heap.length - 1);

} else if (hasLeftChild) {

this.heapSubtree(root, this.heap.length - 1);

}

}

/**

* Gets the root of this.heap.

*

* @return root of this.heap

*/

private int getRoot() {

this.swap(0, this.size - 1);

this.size--;

this.heapSubtree(0, this.size - 1);

return this.heap[this.size]; // return old root

}

/**

* Sorts this.heap with heap sort; displays ordered elements to console.

*

* @return {@code sorted} array of sorted elements

*/

public final int[] sort() {

this.makeMinHeap(0); // make min heap using index 0 as root.

int[] sorted = new int[this.size];

int index = 0;

while (this.size > 0) {

int min = this.getRoot();

sorted[index] = min;

index++;

}

return sorted;

}

/**

* Gets input to sort.

*

* @return unsorted array of integers to sort

*/

public static int[] getInput() {

final int numElements = 6;

int[] unsorted = new int[numElements];

Scanner input = new Scanner(System.in);

System.out.println("Enter any 6 Numbers for Unsorted Array : ");

for (int i = 0; i < numElements; i++) {

unsorted[i] = input.nextInt();

}

input.close();

return unsorted;

}

/**

* Prints elements in heap.

*

* @param heap

* array representing heap

*/

public static void printData(int[] heap) {

System.out.println("Sorted Elements:");

for (int i = 0; i < heap.length; i++) {

System.out.print(" " + heap[i] + " ");

}

}

/**

* Main method.

*

* @param args

* the command line arguments

*/

public static void main(String[] args) {

int[] heap = getInput();

HeapSort data = new HeapSort(heap);

int[] sorted = data.sort();

printData(sorted);

}

}