From f81bffa09c304906e2a09fe28f94d67ac97cf74b Mon Sep 17 00:00:00 2001
From: agampreetsingh <agampreet_singh@yahoo.com>
Date: Tue, 29 Oct 2019 00:53:05 +0530
Subject: [PATCH] Adding LinkedList

---
 Data Structures/LinkedList/LinkedList.java | 160 +++++++++++++++++++++
 1 file changed, 160 insertions(+)
 create mode 100644 Data Structures/LinkedList/LinkedList.java

diff --git a/Data Structures/LinkedList/LinkedList.java b/Data Structures/LinkedList/LinkedList.java
new file mode 100644
index 0000000..ec35c50
--- /dev/null
+++ b/Data Structures/LinkedList/LinkedList.java	
@@ -0,0 +1,160 @@
+package LinkedList;
+
+public class LinkedList {
+
+	private Node head;
+	
+	private int size;
+	
+	private Node tail;
+	
+	public void add(int number) {
+		if(this.size==0) {
+			Node node = new Node();
+			node.setNumber(number);
+			node.setNext(null);
+			this.head=node;
+			this.tail=this.head;
+			this.size++;
+			return;
+		}
+		Node node = new Node();
+		node.setNumber(number);
+		node.setNext(null);
+		this.tail.setNext(node);
+		this.tail=node;
+		this.size++;
+	}
+	
+	
+	public void addFirst(int number) {
+		this.addFirst(this.head,number);
+	}
+	
+	public void addFirst(Node head, int number) {
+		Node node = new Node();
+		node.setNumber(number);
+		node.setNext(head);
+		this.head=node;
+	}
+	
+	
+	
+	public void display() {
+		this.display(this.head);
+	}
+	
+	
+	public void display(Node node) {
+		while(node.getNext()!=null) {
+			System.out.print(node.getNumber()+" ");
+			node=node.getNext();
+		}
+		
+	}
+	
+	public void addAt(int index, int number) throws Exception {
+		if(this.size<index || index<0 ) {
+			throw new Exception("Invalid Index");
+		}
+		else if(index==0) {
+			this.addFirst(number);
+		}
+		else if(index==this.size) {
+			this.add(number);
+		}else {
+			
+		}
+		
+	}
+	
+	public Node getNodeAt(int index) throws Exception {
+		
+		if(index==0) {
+			return this.head;
+		}
+		else if(index==this.size-1) {
+			return this.tail;
+		}
+		else if(index<0 || index>=this.size) {
+			throw new Exception("Invalid Arguments");
+		}
+		
+		Node temp = this.head;
+		for(int i=0;i<index;i++) {
+			temp = temp.getNext();
+		}
+		return temp;
+	}
+	
+	public void reverse() {
+		this.reverse(this.head);
+	}
+	
+	private void reverse(Node head) {
+		
+	}
+	
+	public Node deleteNodeByKey(int key) {
+		return this.deleteNodeByKey(key,this.head);
+	}
+	private Node deleteNodeByKey(int key, Node head) {
+		if(head.getNumber()==key) {
+			this.head=null;
+			this.size--;
+		}
+		
+		Node curr = head.getNext();
+		Node prev = head;
+		while(curr.getNumber()!=key) {
+			prev=curr;
+			curr = curr.getNext();
+		}
+		prev.setNext(curr.getNext());
+		return curr;
+	}
+	
+	
+	public Node deleteNodeByIndex(int index) throws Exception {
+		return this.deleteNodeByIndex(index,this.head);
+	}
+	
+	private Node deleteNodeByIndex(int index, Node head) throws Exception {
+		if(index<0 || index>this.size-1) {
+			throw new Exception("Invalid Index");
+		}
+		
+		if(this.size==1) {
+			Node rv = head;
+			this.head = null;
+			this.size--;
+			return rv;
+		}
+		else if(index==0) {
+			Node rv = this.head;
+			this.head=this.head.getNext();
+			this.size--;
+			return rv;
+		}
+		
+		int i=0;
+		Node curr = head.getNext();
+		Node prev = head;
+		while(i!=index-1) {
+			prev = curr;
+			curr = curr.getNext();
+			i++;
+		}
+		prev.setNext(curr.getNext());
+		this.size--;
+		return curr;
+	}
+	
+	
+	
+	
+	
+	
+	
+}
+