CareerCup_2.1 - Remove Duplicate List Element

MyLinkedList.java

package Chapter2;

//Singly Linked List
public class MyLinkedList<T> {
    public Node<T> head;

    public MyLinkedList(Node<T> h) {
	head = h;
    }

    public MyLinkedList(T[] dataArray) {
	if (dataArray == null || dataArray.length <= 0)
	    return;
	head = new Node<>(dataArray[0], null);
	Node<T> node = head;
	for (int i = 1; i < dataArray.length; i++) {
	    node.next = new Node<T>(dataArray[i], null);
	    node = node.next;
	}
    }

    public void print() {
	Node<T> cur = head;
	while (cur != null) {
	    System.out.print(cur.data);
	    if (cur.next != null) {
		System.out.print(" -> ");
	    }
	    cur = cur.next;
	}
	System.out.println();
    }
}

Node.java

package Chapter2;

public class Node<T> {
    public T data;
    public Node<T> next;
    
    public Node(T d, Node<T> n){
	data = d;
	next = n;
    }
}

RemoveDuplication.java

package Chapter2;

import java.util.HashSet;

public class RemoveDuplication {
    public static <T> void removeDup(MyLinkedList<T> list) {
	if (list == null || list.head == null)
	    return;

	HashSet<T> hashSet = new HashSet<>();
	Node<T> prev = list.head;
	Node<T> cur = list.head.next;
	hashSet.add(list.head.data);

	while (cur != null) {
	    if (hashSet.contains(cur.data)) {
		prev.next = cur.next;
		cur.next = null;
		cur = prev.next;
	    } else {
		hashSet.add(cur.data);
		prev = cur;
		cur = cur.next;
	    }
	}
    }
    
    public static <T> void removeDupNoBuf(MyLinkedList<T> list) { 
	if (list == null || list.head == null)
	    return;
	Node<T> start = list.head;
	while (start != null) {
	    Node<T> prev = start;
	    Node<T> cur = start.next;
	    while (cur != null) {
		if (cur.data == start.data || cur.data == prev.data) {
		    prev.next = cur.next;
		    cur.next = null;
		    cur = prev.next;
		} else {
		    prev = cur;
		    cur = cur.next;
		}
	    }
	    start = start.next;
	}
    }

    public static void main(String[] args) {
	MyLinkedList<Integer> list = new MyLinkedList<>(new Integer[] { 2, 7, 5, 4, 2, 2, 4, 6 });
	list.print();
	removeDup(list);
	list.print();
    }
}