import java.util.*;
public class LinkedList {
private class Node {
int data;
Node next;
Node(int data, Node next) {
this.data = data;
this.next = next;
}
}
private Node head;
private Node tail;
private int size;
public LinkedList() {
this.head = null;
this.tail = null;
this.size = 0;
}
public LinkedList(Node head, Node tail, int size) {
this.head = head;
this.tail = tail;
this.size = size;
}
// O(1)
public int size() {
return this.size;
}
// O(1)
public boolean isEmpty() {
return this.size() == 0;
}
// O(1)
public int getFirst() throws Exception {
if (this.isEmpty()) {
throw new Exception("List is empty.");
}
return this.head.data;
}
// O(1)
public int getLast() throws Exception {
if (this.isEmpty()) {
throw new Exception("List is empty.");
}
return this.tail.data;
}
// O(N)
public int getAt(int idx) throws Exception {
Node temp = this.getNodeAt(idx);
return temp.data;
}
// O(N)
private Node getNodeAt(int idx) throws Exception {
if (this.isEmpty()) {
throw new Exception("List is empty");
}
if (idx < 0 || idx >= this.size()) {
throw new Exception("Invalid arguments");
}
Node retVal = this.head;
for (int i = 0; i < idx; i++) {
retVal = retVal.next;
}
return retVal;
}
// O(1)
public void addFirst(int data) {
Node node = new Node(data, this.head);
if (this.size() == 0) {
this.head = node;
this.tail = node;
} else {
this.head = node;
}
this.size++;
}
// O(1)
public void addLast(int data) {
Node node = new Node(data, null);
if (this.size() == 0) {
this.head = node;
this.tail = node;
} else {
this.tail.next = node;
this.tail = node;
}
this.size++;
}
// O(n)
public void addAt(int idx, int data) throws Exception {
if (idx < 0 || idx > this.size()) {
throw new Exception("Invalid arguments");
}
if (idx == 0) {
this.addFirst(data);
} else if (idx == this.size()) {
this.addLast(data);
} else {
Node nm1 = this.getNodeAt(idx - 1);
Node n = nm1.next;
Node node = new Node(data, n);
nm1.next = node;
this.size++;
}
}
// O(1)
public int removeFirst() throws Exception {
if (this.isEmpty()) {
throw new Exception("List is empty");
}
int retVal = this.head.data;
if (this.size() == 1) {
this.head = null;
this.tail = null;
} else {
this.head = this.head.next;
}
this.size--;
return retVal;
}
// O(n)
public int removeLast() throws Exception {
if (this.isEmpty()) {
throw new Exception("List is empty");
}
int retVal = this.tail.data;
if (this.size() == 1) {
this.head = null;
this.tail = null;
} else {
Node sm2 = this.getNodeAt(this.size() - 2);
sm2.next = null;
this.tail = sm2;
}
this.size--;
return retVal;
}
// O(n)
public int removeAt(int idx) throws Exception {
if (this.isEmpty()) {
throw new Exception("List is empty");
}
if (idx < 0 || idx >= this.size()) {
throw new Exception("Invalid arguments");
}
if (idx == 0) {
return this.removeFirst();
} else if (idx == this.size() - 1) {
return this.removeLast();
} else {
Node nm1 = this.getNodeAt(idx - 1);
Node n = nm1.next;
Node np1 = n.next;
nm1.next = np1;
this.size--;
return n.data;
}
}
// O(n)
public void display() {
Node node = this.head;
while (node != null) {
System.out.print(node.data + " ");
node = node.next;
}
//System.out.println("END");
}
public void reverse(int k){
// Write your code here
Node temp = this.head;
while(temp!=null){
Node temp1 = temp;
int data = temp.data;
for(int i=1;i<k;i++){
if(temp.next!=null)
temp = temp.next;
else
break;
}
temp1.data = temp.data;
temp.data = data;
if(temp.next!=null)
temp = temp.next;
else
break;
}
}
public static void main(String[] args) throws Exception {
Scanner scn = new Scanner(System.in);
int N = scn.nextInt();
int k = scn.nextInt();
LinkedList list = new LinkedList();
for (int i = 0; i < N; i++) {
list.addLast(scn.nextInt());
}
list.reverse(k);
list.display();
}
}
this code gives a
“compilation error: Main.java:2: error: class LinkedList is public, should be declared in a file named LinkedList.java
public class LinkedList {
^
1 error”
but is compiling fine on my VS code