Complete the implementation of the methods in the SimpleLinkedList class. V remo
ID: 3827228 • Letter: C
Question
Complete the implementation of the methods in the SimpleLinkedList class.
V remove(K key), V remove(int n), V lookup(K key), V remove(), size(), V get(int n), and Object[] toArray()
SimpleLinkedList.java
public class SimpleLinkedList<K, V> implements List<K, V> {
private Node head = null;
@Override
public boolean add(K key, V value) {
if (head == null) { // List is empty
Node nn = new Node(key, value);
head = nn;
} else {
Node node = head;
while (node.next != null) {
node = node.next;
}
node.next = new Node(key, value);
}
return true;
}
@Override
public V remove(K key) {
// TODO Auto-generated method stub
return null;
}
@Override
public V remove(int n) {
// TODO Auto-generated method stub
return null;
}
@Override
public V remove() {
// TODO Auto-generated method stub
return null;
}
@Override
public V lookup(K key) {
// TODO Auto-generated method stub
return null;
}
@Override
public int size() {
// TODO Auto-generated method stub
return 0;
}
@Override
public V get(int n) {
// TODO Auto-generated method stub
return null;
}
private class Node {
protected K key;
protected V value;
protected Node next;
Node(K k, V v) {
key = k;
value = v;
next = null;
}
}
@Override
public Object[] toArray() {
return null;
}
@Override
public String toString() {
StringBuilder sb = new StringBuilder();
Node node = head;
while (node != null) {
sb.append("(" + node.key + "," + node.value + ") -- ");
node = node.next;
}
return sb.toString();
}
}
List.java
public interface List {
//abstract methods
public abstract boolean add(K key,V value);
public abstract V remove(K key);
public abstract V remove(int n);
public abstract V remove();
public abstract V lookup(K key);
public abstract int size();
public abstract V get(int n);
public abstract Object[] toArray();
public abstract String toString();
}
Explanation / Answer
import java.util.Scanner;
/* Class Node */
class Node
{
protected int data;
protected Node link;
/* Constructor */
public Node()
{
link = null;
data = 0;
}
/* Constructor */
public Node(int d,Node n)
{
data = d;
link = n;
}
/* Function to set link to next Node */
public void setLink(Node n)
{
link = n;
}
/* Function to set data to current Node */
public void setData(int d)
{
data = d;
}
/* Function to get link to next node */
public Node getLink()
{
return link;
}
/* Function to get data from current Node */
public int getData()
{
return data;
}
}
/* Class linkedList */
class linkedList
{
protected Node start;
protected Node end ;
public int size ;
/* Constructor */
public linkedList()
{
start = null;
end = null;
size = 0;
}
/* Function to check if list is empty */
public boolean isEmpty()
{
return start == null;
}
/* Function to get size of list */
public int getSize()
{
return size;
}
/* Function to insert an element at begining */
public void insertAtStart(int val)
{
Node nptr = new Node(val, null);
size++ ;
if(start == null)
{
start = nptr;
end = start;
}
else
{
nptr.setLink(start);
start = nptr;
}
}
/* Function to insert an element at end */
public void insertAtEnd(int val)
{
Node nptr = new Node(val,null);
size++ ;
if(start == null)
{
start = nptr;
end = start;
}
else
{
end.setLink(nptr);
end = nptr;
}
}
/* Function to insert an element at position */
public void insertAtPos(int val , int pos)
{
Node nptr = new Node(val, null);
Node ptr = start;
pos = pos - 1 ;
for (int i = 1; i < size; i++)
{
if (i == pos)
{
Node tmp = ptr.getLink() ;
ptr.setLink(nptr);
nptr.setLink(tmp);
break;
}
ptr = ptr.getLink();
}
size++ ;
}
/* Function to delete an element at position */
public void deleteAtPos(int pos)
{
if (pos == 1)
{
start = start.getLink();
size--;
return ;
}
if (pos == size)
{
Node s = start;
Node t = start;
while (s != end)
{
t = s;
s = s.getLink();
}
end = t;
end.setLink(null);
size --;
return;
}
Node ptr = start;
pos = pos - 1 ;
for (int i = 1; i < size - 1; i++)
{
if (i == pos)
{
Node tmp = ptr.getLink();
tmp = tmp.getLink();
ptr.setLink(tmp);
break;
}
ptr = ptr.getLink();
}
size-- ;
}
/* Function to display elements */
public void display()
{
System.out.print(" Singly Linked List = ");
if (size == 0)
{
System.out.print("empty ");
return;
}
if (start.getLink() == null)
{
System.out.println(start.getData() );
return;
}
Node ptr = start;
System.out.print(start.getData()+ "->");
ptr = start.getLink();
while (ptr.getLink() != null)
{
System.out.print(ptr.getData()+ "->");
ptr = ptr.getLink();
}
System.out.print(ptr.getData()+ " ");
}
}
/* Class SinglyLinkedList */
public class SinglyLinkedList
{
public static void main(String[] args)
{
Scanner scan = new Scanner(System.in);
/* Creating object of class linkedList */
linkedList list = new linkedList();
System.out.println("Singly Linked List Test ");
char ch;
/* Perform list operations */
do
{
System.out.println(" Singly Linked List Operations ");
System.out.println("1. insert at begining");
System.out.println("2. insert at end");
System.out.println("3. insert at position");
System.out.println("4. delete at position");
System.out.println("5. check empty");
System.out.println("6. get size");
int choice = scan.nextInt();
switch (choice)
{
case 1 :
System.out.println("Enter integer element to insert");
list.insertAtStart( scan.nextInt() );
break;
case 2 :
System.out.println("Enter integer element to insert");
list.insertAtEnd( scan.nextInt() );
break;
case 3 :
System.out.println("Enter integer element to insert");
int num = scan.nextInt() ;
System.out.println("Enter position");
int pos = scan.nextInt() ;
if (pos <= 1 || pos > list.getSize() )
System.out.println("Invalid position ");
else
list.insertAtPos(num, pos);
break;
case 4 :
System.out.println("Enter position");
int p = scan.nextInt() ;
if (p < 1 || p > list.getSize() )
System.out.println("Invalid position ");
else
list.deleteAtPos(p);
break;
case 5 :
System.out.println("Empty status = "+ list.isEmpty());
break;
case 6 :
System.out.println("Size = "+ list.getSize() +" ");
break;
default :
System.out.println("Wrong Entry ");
break;
}
/* Display List */
list.display();
System.out.println(" Do you want to continue (Type y or n) ");
ch = scan.next().charAt(0);
} while (ch == 'Y'|| ch == 'y');
}
}