Question

Complete LinkedListCollection.java with following methods:

public LinkedListCollection();

public LinkedListCollection(int size);

public boolean isEmpty();

public int size(); // Return number of elements in the Collection.

public String toString();

public boolean add(T element); // Add an element into the Collection, return true if successful

public boolean remove(T target); // Remove the target from Collection, return true if successful

public boolean removeAll(T target); // Remove all occurrences of Target, return if successful

public void removeDuplicate(); // Remove duplicated element(s)

public boolean equals(LinkedListCollection that); // Return true if this Collection is same as that Collection

public int count(T target); // Return the number of a given target in the Collection

public void merge(LinkedListCollection that); // Merge this Collection with that Collection

public void enlarge(int size); //Increase this Collection with additional size elements

public void clear(); // Clear entire Collection

public boolean contains(T target); // Return true if the target is in the Collection

package Homework3;

public class LinkedListCollection <T> {

protected Node<T> head = null;

public LinkedListCollection() {

}

public boolean isEmpty() {

return head == null;

}

public int size() {

int counter = 0;

Node<T> cursor = head;

while (cursor != null) {

cursor = cursor.getLink();

counter++;

}

return counter;

}

public String toString() {

Node<T> cursor = head;

String collection = "";

while (cursor != null) {

collection += cursor.getInfo() + "\n";

cursor = cursor.getLink();

}

return collection;

}

public boolean add(T element) {

// Insert at head

Node<T> node = new Node<T>(element);

// Code here

return true;

}

public boolean remove(T target) {

Node<T> cursor = head;

Node<T> previous = head;

while (cursor != null) {

// Code here

previous = cursor;

cursor = cursor.getLink();

}

return false;

}

public boolean removeAll(T target) {

Node<T> cursor = head;

Node<T> previous = head;

boolean found = false;

// Code here

return found;

}

public void removeDuplicate() {

// Remove any duplicated elements

// Code here

}

public boolean equals(LinkedListCollection that) {

// Return true if LinkedListCollection are identical.

boolean result = true;

Node<T> cursor_this = head;

Node<T> cursor_that = that.head;

while (cursor_this != null && cursor_that != null) {

if (!cursor_this.getInfo().equals(cursor_that.getInfo()))

result = false;

cursor_this = cursor_this.getLink();

cursor_that = cursor_that.getLink();

}

return result && this.size() == that.size();

}

public int count(T target) {

// Return count of target occurrences

int c = 0;

Node<T> cursor = head;

// Code here

return c;

}

public void merge(LinkedListCollection that) {

// Merge that LinkedListCollection into this LinkedListCollection

if (that.head == null) return; // Nothing to merge

if (this == that) return; // Same list

// Code here

}

public void clear() {

// Remove all elements in the collection

}

public boolean contains(T target) {

// Return true if target is found

boolean found = false;

Node<T> cursor = head;

// Code here

return found;

}

}

Answer 1

The following code have all the "Code here" filled.

public class LinkedListCollection <T> {

protected Node<T> head = null;

public LinkedListCollection() {

}

public boolean isEmpty() {

return head == null;

}

public int size() {

int counter = 0;

Node<T> cursor = head;

while (cursor != null) {

cursor = cursor.getLink();

counter++;

}

return counter;

}

public String toString() {

Node<T> cursor = head;

String collection = "";

while (cursor != null) {

collection += cursor.getInfo() + "\n";

cursor = cursor.getLink();

}

return collection;

}

public boolean add(T element) {

// Insert at head

Node<T> node = new Node<T>(element);

// Code here
//setting head as it's next element, now head is the second element and node links to head
node.setLink(head);
//setting node as the new head, so that node is called wherever head is neaded
head = node;

return true;

}

public boolean remove(T target) {

Node<T> cursor = head;

Node<T> previous = head;

while (cursor != null) {

// Code here
// if the current Node's Info is equal to Target,
//then we link previous Node to the next NOde, unlinking self from the chain
if(cursor.getInfo() == target){
//Linking next Node to the previous
previous.setLink(cursor.getLink());
//returning true, returning stops the function
//so no need to worry about loop anymore
return true;
}

previous = cursor;

cursor = cursor.getLink();

}

return false;

}

public boolean removeAll(T target) {

Node<T> cursor = head;

Node<T> previous = head;

boolean found = false;

// Code here
//creating loop to traverse node by node till there is no next node
while (cursor != null) {
// if the current Node's Info is equal to Target,
if(cursor.getInfo() == target){
//then we link previous Node to the next NOde, unlinking self from the chain
previous.setLink(cursor.getLink());
//setting cursor to next node to traverse further
cursor = cursor.getLink();
//setting found to true
found = true;
//continue directly starts the next iteration of loop
//doing this because we already set the next no need to execute further
continue;
}
//in case target does not match current nodes data
//then we set current node as previoous
//and set next nose as current
previous = cursor;

cursor = cursor.getLink();

}

return found;

}

public void removeDuplicate() {

// Remove any duplicated elements

// Code here
//Creating another Linked List that will not hold any duplicate data
LinkedListCollection <T> other = new LinkedListCollection <T>();
//setting this LL's cursor
Node<T> cursor_this = head;
//setting No duplicate LL's cursor
Node<T> cursor_other = head;
//Traversing through the LL with duplicate entries
while (cursor_this != null){
//if (LL with no duplicates) does not have the Info of current node of (LL that have duplicate)
if(!other.contains(cursor_this.getInfo())){
//then we add this link to the LL with no Duplicates
cursor_other.setLink(cursor_this);
//updating cursor of No duplicate LL i.e, other
//so that we can further add to it whenever new non-duplicate node appears
cursor_other= cursor_other.getLink();
}
//setting next node of duplicate as current node in traversing
cursor_this = cursor_this.getLink();
  
}

}

public boolean equals(LinkedListCollection that) {

// Return true if LinkedListCollection are identical.

boolean result = true;

Node<T> cursor_this = head;

Node<T> cursor_that = that.head;

while (cursor_this != null && cursor_that != null) {

if (!cursor_this.getInfo().equals(cursor_that.getInfo()))

result = false;

cursor_this = cursor_this.getLink();

cursor_that = cursor_that.getLink();

}

return result && this.size() == that.size();

}

public int count(T target) {

// Return count of target occurrences

int c = 0;

Node<T> cursor = head;

// Code here
//traversing through the LL
while (cursor != null) {
//adding the count by 1 on every element tha is traversed
c++;
//setting next node as the current node
cursor = cursor.getLink();

}

return c;

}

public void merge(LinkedListCollection that) {

// Merge that LinkedListCollection into this LinkedListCollection

if (that.head == null) return; // Nothing to merge

if (this == that) return; // Same list

// Code here
//creating cursor to traverse through list
Node<T> cursor= this.head;
//running infinite loop
while (true) {
//if next node is null
//that means we have reached the last of 'this' LL
if(cursor.getLink() == null){
//linking the head of 'that' as the last node's next of 'this'
cursor.setLink(that.head);
//stoping the loop
break;
}
//setting next node as the current node
cursor = cursor.getLink();

}

}

public void clear() {

// Remove all elements in the collection

//code here
//setting head of the LL to null
//every LL starts from head, if head is null there is no LL
this.head = null;

}

public boolean contains(T target) {

// Return true if target is found

boolean found = false;

Node<T> cursor = head;

// Code here
//traversing every node of the LL
while (cursor != null) {
//matching the nodes info to target
if(cursor.getInfo() == target){
//detting found = true so that true is returned
found= true;
}

//setting next node as the current node
cursor = cursor.getLink();

}

return found;

}

}

This is the indentation:

Happy to help :)