Question

Can you help with the merge method? This method should create and return an ArrayBagcontaining one occurrence of any item that is found in either the called object or the parameter other. For full credit, the resulting bag should not include any duplicates. Give the new ArrayBag a maximum size that is the sum of the two bag’s maximum sizes.

import java.util.*;

/**

* An implementation of a bag data structure using an array.

*/

public class ArrayBag {

/**

   * The array used to store the items in the bag.

   */

private Object[] items;

  

/**

   * The number of items in the bag.

   */

private int numItems;

  

public static final int DEFAULT_MAX_SIZE = 50;

  

/**

   * Constructor with no parameters - creates a new, empty ArrayBag with

   * the default maximum size.

   */

public ArrayBag() {

this.items = new Object[DEFAULT_MAX_SIZE];

this.numItems = 0;

}

public int capacity() {

//return the max number of items the ArrayBag is able to hold

return items.length;

}

public boolean isEmpty() {

//should return true if the arraybag is empty, and false otherwise

return numItems == 0;

}

public boolean addAll(Object[] newItems) {

//This method should attempt to add to the called ArrayBag

//all of the items found in the array newItems that is passed as a

//parameter, and it should return a

//boolean value indicating success or failure.

//int n stores how many items are stored

int n = newItems.length;

int remain_space = this.items.length - this.numItems;

//if n > than remainspace we return false

if(n>remain_space) {

return false;

}

//add all the items in array to newItems into item[] and return true

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

this.items[this.numItems] = newItems[i];

this.numItems++;

}

return true;

}

  

/**

   * A constructor that creates a new, empty ArrayBag with the specified

   * maximum size.

   */

public ArrayBag(int maxSize) {

if (maxSize <= 0) {

throw new IllegalArgumentException("maxSize must be > 0");

}

this.items = new Object[maxSize];

this.numItems = 0;

}

public ArrayBag merge(ArrayBag other) {

//This method should create and return an ArrayBag

//containing one occurrence of any item that is found in

//either the called object or the parameter other.

int n1 = numItems();

int n2 = numItems();

boolean duplicate = false;

//delcare object items

ArrayBag result = new ArrayBag(n1+n2);

if(n1<n2)

{

for(int i=0;i<n1;i++)

{

for(int j=0;j<n1;j++)

{

if(items[i] != items[j])

{

continue;

}

else

duplicate=true;

}

if(duplicate!=true)

{

  

result.add(items[i]);

}

}

  

for(int i=n1;i<n2;i++)

{

result.add(items[i]);

}

}

return result;

}

  

/**

   * numItems - accessor method that returns the number of items

   * in this ArrayBag.

   */

public int numItems() {

return this.numItems;

}

  

/**

   * add - adds the specified item to this ArrayBag. Returns true if there

   * is room to add it, and false otherwise.

   * Throws an IllegalArgumentException if the item is null.

   */

public boolean add(Object item) {

if (item == null) {

throw new IllegalArgumentException("item must be non-null");

} else if (this.numItems == this.items.length) {

return false; // no more room!

} else {

this.items[this.numItems] = item;

this.numItems++;

return true;

}

}

  

/**

   * remove - removes one occurrence of the specified item (if any)

   * from this ArrayBag. Returns true on success and false if the

   * specified item (i.e., an object equal to item) is not in this ArrayBag.

   */

public boolean remove(Object item) {

for (int i = 0; i < this.numItems; i++) {

if (this.items[i].equals(item)) {

// Shift the remaining items left by one.

for (int j = i; j < this.numItems - 1; j++) {

this.items[j] = this.items[j + 1];

}

this.items[this.numItems - 1] = null;

  

this.numItems--;

return true;

}

}

  

return false; // item not found

}

  

/**

   * contains - returns true if the specified item is in the Bag, and

   * false otherwise.

   */

public boolean contains(Object item) {

for (int i = 0; i < this.numItems; i++) {

if (this.items[i].equals(item)) {

return true;

}

}

  

return false;

}

  

/**

   * grab - returns a reference to a randomly chosen item in this ArrayBag.

   */

public Object grab() {

if (this.numItems == 0) {

throw new IllegalStateException("the bag is empty");

}

  

int whichOne = (int)(Math.random() * this.numItems);

return this.items[whichOne];

}

  

/**

   * toArray - return an array containing the current contents of the bag

   */

public Object[] toArray() {

Object[] copy = new Object[this.numItems];

  

for (int i = 0; i < this.numItems; i++) {

copy[i] = this.items[i];

}

  

return copy;

}

  

/**

   * toString - converts this ArrayBag into a string that can be printed.

   * Overrides the version of this method inherited from the Object class.

   */

public String toString() {

String str = "{";

  

for (int i = 0; i < this.numItems; i++) {

str = str + this.items[i];

if (i != this.numItems - 1) {

str += ", ";

}

}

  

str = str + "}";

return str;

}

  

/* Test the ArrayBag implementation. */

public static void main(String[] args) {

}

Answer 1

CODE

public ArrayBag merge(ArrayBag other) {

//This method should create and return an ArrayBag

//containing one occurrence of any item that is found in

//either the called object or the parameter other.

int n1 = this.numItems();

int n2 = other.numItems();

boolean duplicate = false;

//declare object items

ArrayBag result = new ArrayBag(n1+n2);

Object duplicates[] = new Object[n1 + n2];

int k = 0;

for(int i=0;i<n1;i++)

{

for(int j=0;j<n2;j++)

{

if(items[i] == other.items[j])

{

duplicates[k ++] = items[i];

}

}

}

for(int i=0; i<n1; i++)

{

result.add(items[i]);

}

for (int i=0; i<n2; i++) {

for (int j=0; j<k; j++) {

if (other.items[i] == duplicates[k]) {

duplicate = true;

break;

}

}

if (!duplicate) {

result.add(other.items[i]);

}

}

return result;

}