@@ -17,11 +17,6 @@ class SinglyLinkedList {
1717 */
1818private Node head ;
1919
20- /**
21- * Count of nodes
22- */
23- private int count ;
24-
2520/**
2621 * This method inserts an element at the head
2722 *
@@ -31,7 +26,6 @@ public void insertHead(int x) {
3126Node newNode =new Node (x );
3227newNode .next =head ;
3328head =newNode ;
34- ++count ;
3529 }
3630
3731/**
@@ -42,35 +36,51 @@ public void insertHead(int x) {
4236 */
4337
4438public void insertNth (int data ,int position ) {
45- if (position <0 ||position >count ) {
39+ if (position <0 ||position >getSize () ) {
4640throw new RuntimeException ("position less than zero or position more than the count of list" );
4741 }
48- Node node =new Node (data );
49- Node dummy =new Node (-1 );
50- dummy .next =head ;
51- Node cur =dummy ;
52- for (int i =0 ;i <position ; ++i ) {
53- cur =cur .next ;
42+ else if (position ==0 )
43+ insertHead (data );
44+ else {
45+ Node cur =head ;
46+ Node node =new Node (data );
47+ for (int i =1 ;i <position ; ++i ) {
48+ cur =cur .next ;
49+ }
50+ node .next =cur .next ;
51+ cur .next =node ;
5452 }
55- node .next =cur .next ;
56- cur .next =node ;
57- ++count ;
5853 }
5954
6055/**
6156 * This method deletes an element at the head
6257 *
6358 * @return The element deleted
6459 */
65- public Node deleteHead () {
60+ public void deleteHead () {
6661if (isEmpty ()) {
6762throw new RuntimeException ("The list is empty!" );
6863 }
6964
70- Node temp =head ;
7165head =head .next ;
72- --count ;
73- return temp ;
66+ }
67+
68+ /**
69+ * This method deletes an element at Nth position
70+ */
71+ public void deleteNth (int position ) {
72+ if (position <0 ||position >getSize ()) {
73+ throw new RuntimeException ("position less than zero or position more than the count of list" );
74+ }
75+ else if (position ==0 )
76+ deleteHead ();
77+ else {
78+ Node cur =head ;
79+ for (int i =1 ;i <position ; ++i ) {
80+ cur =cur .next ;
81+ }
82+ cur .next =cur .next .next ;
83+ }
7484 }
7585
7686/**
@@ -79,7 +89,7 @@ public Node deleteHead() {
7989 * @return true is list is empty
8090 */
8191public boolean isEmpty () {
82- return count ==0 ;
92+ return getSize () ==0 ;
8393 }
8494
8595/**
@@ -94,6 +104,23 @@ public void display() {
94104System .out .println ();
95105 }
96106
107+ /**
108+ * Returns the size of the linked list
109+ */
110+ public int getSize () {
111+ if (head ==null )
112+ return 0 ;
113+ else {
114+ Node current =head ;
115+ int size =1 ;
116+ while (current .next !=null ) {
117+ current =current .next ;
118+ size ++;
119+ }
120+ return size ;
121+ }
122+ }
123+
97124/**
98125 * Main method
99126 *
@@ -117,6 +144,11 @@ public static void main(String args[]) {
117144myList .insertNth (11 ,2 );
118145
119146myList .display ();// 7 -> 5 -> 11
147+
148+ myList .deleteNth (1 );
149+
150+ myList .display ();// 7-> 11
151+
120152 }
121153}
122154
@@ -145,5 +177,6 @@ class Node {
145177 */
146178Node (int value ) {
147179this .value =value ;
180+ this .next =null ;
148181 }
149182}