Singly and Doubly Linked List have the following methods: Insertion: insertAt, i
ID: 3871687 • Letter: S
Question
Singly and Doubly Linked List have the following methods:
Insertion: insertAt, insertAtFront, and insertAtEnd
Deletion: removeAt, removeAtFront, and removeAtEnd
InsertAtFront and removeAtFront calls insertAt and removeAt by passing 0 as an index respectively. Moreover, insertAtEnd and removeAtEnd calls insertAt and removeAt by passing size (number of elements in Linked List) as an index respectively.
Write insertAt and removeAt methods (one for Singly and one for Doubly Linked List) that inserts and removes an elements from the List by index.
Explanation / Answer
SinglyLinkedList.java:
/* Class Node */
class Node
{
private int data;
private 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 SinglyLinkedList */
class SinglyLinkedList
{
private Node start;
private Node end ;
private int size ;
/* Constructor */
public SinglyLinkedList()
{
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 position 1 to n */
public void insertAt(int val , int pos)
{
Node nptr = new Node(val, null);
if(pos == 1) {
nptr.setLink(start);
start = nptr;
size++ ;
return;
}
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 1 to n */
public void removeAt(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-- ;
}
}
===================================================================
DoublyLinkedList.java:
class Node
{
private int data;
private Node next, prev;
/* Constructor */
public Node()
{
next = null;
prev = null;
data = 0;
}
/* Constructor */
public Node(int d, Node n, Node p)
{
data = d;
next = n;
prev = p;
}
/* Function to set link to next node */
public void setLinkNext(Node n)
{
next = n;
}
/* Function to set link to previous node */
public void setLinkPrev(Node p)
{
prev = p;
}
/* Funtion to get link to next node */
public Node getLinkNext()
{
return next;
}
/* Function to get link to previous node */
public Node getLinkPrev()
{
return prev;
}
/* Function to set data to node */
public void setData(int d)
{
data = d;
}
/* Function to get data from node */
public int getData()
{
return data;
}
}
/* Class DoublyLinkedList */
class DoublyLinkedList
{
private Node start;
private Node end ;
private int size;
/* Constructor */
public DoublyLinkedList()
{
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 element at position 1 to n*/
public void insertAt(int val , int pos)
{
Node nptr = new Node(val, null, null);
if (pos == 1)
{
if(start == null)
{
start = nptr;
end = start;
}
else
{
start.setLinkPrev(nptr);
nptr.setLinkNext(start);
start = nptr;
}
size++;
return;
}
Node ptr = start;
for (int i = 2; i <= size; i++)
{
if (i == pos)
{
Node tmp = ptr.getLinkNext();
ptr.setLinkNext(nptr);
nptr.setLinkPrev(ptr);
nptr.setLinkNext(tmp);
tmp.setLinkPrev(nptr);
}
ptr = ptr.getLinkNext();
}
size++ ;
}
/* Function to delete node at position 1 to n*/
public void removeAt(int pos)
{
if (pos == 1)
{
if (size == 1)
{
start = null;
end = null;
size = 0;
return;
}
start = start.getLinkNext();
start.setLinkPrev(null);
size--;
return ;
}
if (pos == size)
{
end = end.getLinkPrev();
end.setLinkNext(null);
size-- ;
}
Node ptr = start.getLinkNext();
for (int i = 2; i <= size; i++)
{
if (i == pos)
{
Node p = ptr.getLinkPrev();
Node n = ptr.getLinkNext();
p.setLinkNext(n);
n.setLinkPrev(p);
size-- ;
return;
}
ptr = ptr.getLinkNext();
}
}
}