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Following codes contain a class in which we implemented a priority queue using a

ID: 3828136 • Letter: F

Question

 Following codes contain a class in which we implemented a priority queue using an array-based heap.   Complete the heapOrderValid() and isCompleteTree() methods which verify that the data in store has the specified property.  I do rate the answer, so please answer it as accurate as possible, Thanks   package edu.cse116;  import java.util.AbstractCollection; import java.util.Arrays; import java.util.Iterator; import java.util.NoSuchElementException;  /**  * Implementation of a priority queue using an array-based binary tree. This is used to help students understand the  * basic properties binary trees and will have more details explained in future lectures.  *  * @author William J. Collins  * @author Matthew Hertz  * @param  Data type (which must be Comparable) of the elements in this tree.  */ public class PriorityQueue> extends AbstractCollection {   /** Index where the root node can be found. */   private static final int ROOT = 0;    /** Array used to store the elements in the binary tree. */   private E[] store;    /** Number of elements within the tree. */   private int size;    /**    * Initializes this ArrayBinaryTree object to be empty. This creates the array in which items will be stored.    */   @SuppressWarnings("unchecked")   public PriorityQueue() {     store = (E[]) new Comparable[31];     size = 0;   }    /**    * Checks if the binary tree contains an element at the given index. This requires checking both that the array is    * large enough (to avoid triggering an exception) AND (when the array is large enough) that the array has a non-null    * value at that index.    *    * @param idx Index to be checked out.    * @return True if there is an element at the given index; false otherwise.    */   private boolean nodeExists(int idx) {     boolean arrayLocationExists = idx < store.length;     return arrayLocationExists && (store[idx] != null);   }    /**    * Given an index, returns the element in that node's left child. If the left child node does not exist, null should    * be returned. It is important that this NOT trigger an index out of bounds exception.    *    * @param idx Index of the node for which we want the left child.    * @return Value of the node's left child or null if no left child exists.    */   private E leftChild(int idx) {     int leftChild = (idx * 2) + 1;     if (!nodeExists(leftChild)) {       return null;     }     return store[leftChild];   }    /**    * Given an index, returns the element in that node's right child. If the right child node does not exist, null should    * be returned. It is important that this NOT trigger an index out of bounds exception.    *    * @param idx Index of the node for which we want the right child.    * @return Value of the node's right child or null if no right child exists.    */   private E rightChild(int idx) {     int rightChild = (idx * 2) + 2;     if (!nodeExists(rightChild)) {       return null;     }     return store[rightChild];   }    /**    * Given an index, returns the value of that node's parent. If the node is the root (and so has no parent), null    * should be returned. It is important that this NOT trigger an index out of bounds exception.    *    * @param idx Index of the node for which we want the parent.    * @return Value of the node's parent or null if no parent exists.    */   private E parent(int idx) {     int parent = (idx - 1) / 2;     if (idx == ROOT) {       return null;     }     return store[parent];   }    /**    * Returns the size of this ArrayBinaryTree object.    *    * @return the size of this ArrayBinaryTree object.    */   @Override   public int size() {     return size;   }    /**    * Returns an iterator that will return the elements in this ArrayBinaryTree, but without any specific ordering.    *    * @return Iterator positioned at the smallest element in this ArrayBinaryTree object.    */   @Override   public Iterator iterator() {     // Skipped for now.     throw new UnsupportedOperationException();   }    /**    * Adds the specified element to this heap in the appropriate position according to its key value.    *    * @param obj the element to be added to the heap    * @return Since this method will always succeed, it only returns true.    */   @Override   public boolean add(E obj) {     // Make certain the store has space to add an element.     if (size == store.length) {       store = Arrays.copyOf(store, store.length * 2);     }     store[size] = obj;     size += 1;     // We will discuss what must happen here so that we guarantee the heap order property on Monday     return true;   }    /**    * Remove the element with the lowest value in this heap and returns a reference to it. Throws an    * NoSuchElementException if the heap is empty.    *    * @return the element with the lowest value in this heap    */   public E remove() {     if (isEmpty()) {       throw new NoSuchElementException("Cannot call remove on an empty LinkedHeap");     }     E retVal = store[0];     store[0] = store[size - 1];     size -= 1;     // We will discuss what must happen here so that we guarantee the heap order property on Monday     return retVal;   }    /**    * Returns the element with the lowest value in this heap. Throws an NoSuchElementException if the heap is empty.    *    * @return the element with the lowest value in this heap    */   public E element() {     if (isEmpty()) {       throw new NoSuchElementException("Cannot call remove on an empty LinkedHeap");     }     return store[0];   }    public boolean heapOrderValid() {    }    public boolean isCompleteTree() {    } } 

Explanation / Answer

import java.util.AbstractCollection; import java.util.Arrays; import java.util.Iterator; import java.util.NoSuchElementException; public class PriorityQueue> extends AbstractCollection { private static final int ROOT = 0; private E[] store; private int size; @SuppressWarnings("unchecked") public PriorityQueue() { store = (E[]) new Comparable[31]; size = 0; } private boolean nodeExists(int idx) { boolean arrayLocationExists = idx