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added pointers #39

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6a7b94a
added pointers
SubashreeMahendran Oct 13, 2019
b41de0d
input is public
SubashreeMahendran Oct 13, 2019
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336 changes: 230 additions & 106 deletions DataStructures/LinkedList.java
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Original file line number Diff line number Diff line change
@@ -1,123 +1,247 @@
package DataStructures;

import java.util.Scanner;

public class LinkedList {

private Node head;
static class Node {
Node next;
int data;
public Node(int data) {
this.data = data;
next = null;
}

/* Class Node */
class Node
{
public int data;
public 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;
}

public void print() {
Node node = head;
while(node != null) {
System.out.print(node.data + "\t");
node = node.next;
}
}

/* Class linkedList */
class linkedList
{
public Node start;
public Node end ;
public int size ;

/* Constructor */
public linkedList()
{
start = null;
end = null;
size = 0;
}

private void insertFront(int new_data) {
Node newNode = new Node(new_data);
if (head == null) {
head = newNode;
return;
}
newNode.next = head;
head = newNode;
/* Function to check if list is empty */
public boolean isEmpty()
{
return start == null;
}

private void insertBetween(int new_data, Node prevNode, Node nextNode) {
Node newNode = new Node(new_data);
if (head == null || prevNode == null) {
head = newNode;
return;
/* 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;
}
prevNode.next = newNode;
newNode.next = nextNode;
}

private void insertEnd(int new_data) {
Node newNode = new Node(new_data);
if (head == null) {
head = newNode;
return;
/* 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;
}
Node temp = head;
while (temp.next != null) {
temp = temp.next;
else
{
end.setLink(nptr);
end = nptr;
}
temp.next = newNode;
newNode.next = null;
}

private void search(int data) {
Node key = head;
if (head.data == data) {
System.out.println("Key Node: " + head.data);
/* 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;
}
while(key.data != data) {
key = key.next;
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();
}
System.out.println("Search Node Data is " + key.data);
}

public void delete(int data) {
Node temp = head, prev = null;
if (temp != null && temp.data == data) {
head = temp.next;
size-- ;
}
/* Function to display elements */
public void display()
{
System.out.print("\nSingly Linked List = ");
if (size == 0)
{
System.out.print("empty\n");
return;
}
if (start.getLink() == null)
{
System.out.println(start.getData() );
return;
}
while(temp != null && temp.data != data) {
prev = temp;
temp = temp.next;
Node ptr = start;
System.out.print(start.getData()+ "->");
ptr = start.getLink();
while (ptr.getLink() != null)
{
System.out.print(ptr.getData()+ "->");
ptr = ptr.getLink();
}
if (temp == null) return;
prev.next = temp.next;
}

public static void main(String args[]) {
Scanner s = new Scanner(System.in);
LinkedList list = new LinkedList();
list.head = new Node(s.nextInt());
Node secondNode = new Node(s.nextInt());
Node thirdNode = new Node(s.nextInt());

list.head.next = secondNode;
secondNode.next = thirdNode;
thirdNode.next = null;
list.print();
System.out.println();

System.out.println("Insert Data in Front...");
list.insertFront(s.nextInt());
list.print();
System.out.println();

System.out.println("Insert Data in between...");
list.insertBetween(s.nextInt(), secondNode, thirdNode);
list.print();
System.out.println();

System.out.println("Insert Data at end...");
list.insertEnd(s.nextInt());
list.print();
System.out.println();

System.out.println("Search Data...");
list.search(s.nextInt());
//list.print();
System.out.println();

System.out.println("Delete Node...");
list.delete(s.nextInt());
list.print();
System.out.println();
System.out.print(ptr.getData()+ "\n");
}
}

/* 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\n");
char ch;
/* Perform list operations */
do
{
System.out.println("\nSingly Linked List Operations\n");
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\n");
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\n");
else
list.deleteAtPos(p);
break;
case 5 :
System.out.println("Empty status = "+ list.isEmpty());
break;
case 6 :
System.out.println("Size = "+ list.getSize() +" \n");
break;
default :
System.out.println("Wrong Entry \n ");
break;
}
/* Display List */
list.display();
System.out.println("\nDo you want to continue (Type y or n) \n");
ch = scan.next().charAt(0);
} while (ch == 'Y'|| ch == 'y');
}
}