The next exercise is based on this implemetation for an OrderedArrayList of inte
ID: 3683038 • Letter: T
Question
The next exercise is based on this implemetation for an OrderedArrayList of integers:
//Interface: ArrayListADT
public interface ArrayListADT {
//same as above, you already have it!
}
//Class: ArrayListClass implements
//Interface: ArrayListADT
public abstract class ArrayListClass implements ArrayListADT {
//same as above, you already have it!
}
//Class: OrderedArrayList extends
//Super class: ArrayListClass
public class OrderedArrayList extends ArrayListClass{
public OrderedArrayList() {
super();
}
public OrderedArrayList(int size) {
super(size);
}
//implementation for abstract methods defined in ArrayListClass
//ordered list --> binary search
public int search(int item) {
int first = 0;
int last = length - 1;
int middle = -1;
while (first <= last) {
middle = (first + last) / 2;
if (list[middle] == item)
return middle;
else
if (list[middle] > item)
last = middle - 1;
else
first = middle + 1;
}
return -1;
}
public void insert(int item) {
int loc;
boolean found = false;
if (length == 0) //list is empty
list[length++] = item; //insert item and increment length
else if (length == maxSize) //list is full
System.err.println("Cannot insert in a full list.");
else {
for (loc = 0; loc < length; loc++) {
if (list[loc] >= item) {
found = true;
break;
}
}
//starting at the end, shift right
for (int i = length; i > loc; i--)
list[i] = list[i - 1];
list[loc] = item; //insert in place
length++;
}
}
/* Another version for insert:
public void insert(int item) {
int loc;
boolean found = false;
if (length == 0) //list is empty
list[length++] = item; //insert item and increment length
else if (length == maxSize) //list is full
System.err.println("Cannot insert in a full list.");
else {
int i = length - 1;
while (i >= 0 && list[i] > item) {
list[i + 1] = list[i];
i--;
}
list[i + 1] = item; // Insert item
length++;
}
} */
public void insertAt(int location, int item) {
if (location < 0 || location >= maxSize)
System.err.println("The position of the item to be inserted is out of range.");
else if (length == maxSize) //the list is full
System.err.println("Cannot insert in a full list.");
else {
System.out.println("Cannot do it, this is a sorted list. Doing insert in place (call to insert).");
insert(item);
}
}
public void insertEnd(int item) {
if (length == maxSize) //the list is full
System.err.println("Cannot insert in a full list.");
else {
System.out.println("Cannot do it, this is a sorted list. Doing insert in place (call to insert).");
insert(item);
}
}
public void replaceAt(int location, int item) {
//the list is sorted!
//is actually removing the element at location and inserting item in place
if (location < 0 || location >= length)
System.err.println("The position of the item to be replaced is out of range.");
else {
removeAt(location);//method in ArrayListClass
insert(item);
}
}
public void remove(int item) {
int loc;
if (length == 0)
System.err.println("Cannot delete from an empty list.");
else {
loc = search(item);
if (loc != -1)
removeAt(loc);//method in ArrayListClass
else
System.out.println("The item to be deleted is not in the list.");
}
}
/*Another version for remove:
public void remove(T item) {
int loc;
if (length == 0)
System.err.println("Cannot delete from an empty list.");
else {
loc = search(item);
if (loc != -1) {
for(int i = loc; i < length - 1; i++)
list[i] = list[i + 1]; //shift left
length--;
}
else
System.out.println("The item to be deleted is not in the list.");
}
} */
}
2.1. Add to class OrderedArrayList a new method called removeDuplicates that should eliminate any duplicates from a sorted list. For example, if the list is: [2, 2, 2, 2, 5, 5, 8, 9, 9, 9 ] before the method is invoked, it should be [2, 5, 8, 9 ] after the method executes. Test the method using this client:
//Testing the method removeDuplicates added to the user created OrderedArrayList class
public class Lab8_3 {
public static void main(String[] args) {
OrderedArrayList list = new OrderedArrayList();
list.insert(8);
list.insert(2);
list.insert(2);
list.insert(9);
list.insert(5);
list.insert(9);
list.insert(2);
list.insert(9);
list.insert(2);
list.insert(5);
System.out.println("The original list is: ");
list.print();
System.out.println("The list after method call is: ");
list.removeDuplicates();
list.print();
}
}
2.2. Same problem. This time use the ArrayList class in Java. Write removeDuplicates as a client method and use the print method provided.
//Testing the method removeDuplicates using the Java ArrayList class
import java.util.ArrayList;
public class Lab8_4 {
public static void main(String[] args) {
ArrayList <Integer> list = new ArrayList <Integer>();
list.add(2);
list.add(2);
list.add(2);
list.add(5);
list.add(5);
list.add(8);
list.add(9);
list.add(9);
System.out.println("The original list is: ");
print(list);
System.out.println("The list after method call is: ");
removeDuplicates(list);
print(list);
}
public static void removeDuplicates(ArrayList<Integer> list) {
...
}
public static void print(ArrayList <Integer> someList) {
for(Integer i:someList)
System.out.print(i + " ");
System.out.println();
}
}
Explanation / Answer
Program plan: here i am providing the code for removeDuplicate() method.plaese add it to the main class because i didnot have the previous interface definition to run the entire program.thank you
Method Definition:
To remove the duplicates we can use HashSet class because HashSet stores only unique values not repeated values hence adding the all elements of ArrayList elements to HashSet/LinkedHashSet.If we add List elements to HashSet then the duplicates automatically deleted then we can print the unique values.or else we can now clear the List element and then add the HashSet elements to ArrayList.
2.1: Here removeDuplicate and print ara the member functions of OrderedList class.these to should add to that class
void removeDuplicates()
{
//Instantiating the LinkedHashSet class variable
LinkedHashSet<Integer> l=new LinkedHashSet<Integer>();
//adding the ArrayList class elments to LinkedHashSet object
//it automatically removes all duplicate values
l.addAll(list);
list.clear();//this make the list empty
//now we can add LinkedHashSet elements to ArrayList
list.addAll(l);
}
void print() {
for(Integer i:list)
System.out.print(i + " ");
System.out.println();
}
Now the main class will modify like this
//Testing the method removeDuplicates added to the user created OrderedArrayList class
public class Lab8_3 {
public static void main(String[] args) {
OrderedArrayList list = new OrderedArrayList();
list.insert(8);
list.insert(2);
list.insert(2);
list.insert(9);
list.insert(5);
list.insert(9);
list.insert(2);
list.insert(9);
list.insert(2);
list.insert(5);
System.out.println("The original list is: ");
//we are calling these by using the object of OrderedList class
list.print();
System.out.println("The list after method call is: ");
list.removeDuplicates();
list.print();
}
}
2.2:Here the definition of the methods has static keyword hence we need not to use class object to call these function hence the definition follows like public static void ramoveDuplicates()
public static void removeDuplicates(ArrayList<Integer> list)
{
//Instantiating the LinkedHashSet class variable
LinkedHashSet<Integer> l=new LinkedHashSet<Integer>();
//adding the ArrayList class elments to LinkedHashSet object
//it automatically removes all duplicate values
l.addAll(list);
list.clear();//this make the list empty
//now we can add LinkedHashSet elements to ArrayList
list.addAll(l);
}
public static void print(ArrayList <Integer> someList) {
for(Integer i:someList)
System.out.print(i + " ");
System.out.println();
}
now the second main will change like this.
//Testing the method removeDuplicates using the Java ArrayList class
import java.util.ArrayList;
public class Lab8_4 {
public static void main(String[] args) {
ArrayList <Integer> list = new ArrayList <Integer>();
list.add(2);
list.add(2);
list.add(2);
list.add(5);
list.add(5);
list.add(8);
list.add(9);
list.add(9);
System.out.println("The original list is: ");
print(list);
System.out.println("The list after method call is: ");
removeDuplicates(list);
print(list);
}
Thank you....
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