Question.java

package Question2_1;

import java.util.Hashtable;

import CareerCupLibrary.AssortedMethods;
import CareerCupLibrary.LinkedListNode;

public class Question {

	public static void deleteDups(LinkedListNode n) {
		Hashtable table = new Hashtable();
		LinkedListNode previous = null;
		while (n != null) {
			if (table.containsKey(n.data)) {
				previous.next = n.next;
			} else {
				table.put(n.data, true);
				previous = n;
			}
			n = n.next;
		}
	}
	
	public static void deleteDups2(LinkedListNode head) {
		if (head == null) return;
		LinkedListNode previous = head;
		LinkedListNode current = previous.next;
		while (current != null) {
			// Look backwards for dups, and remove any that you see.
			LinkedListNode runner = head;
			while (runner != current) { 
				if (runner.data == current.data) {
					LinkedListNode tmp = current.next;
					previous.next = tmp;
					current = tmp;
					/* We know we can�t have more than one dup preceding
					 * our element since it would have been removed 
					 * earlier. */
				    break;
				}
				runner = runner.next;
			}

			/* If runner == current, then we didn�t find any duplicate 
			 * elements in the previous for loop.  We then need to 
			 * increment current.  
			 * If runner != current, then we must have hit the �break� 
			 * condition, in which case we found a dup and current has
			 * already been incremented.*/
			if (runner == current) {
				previous = current;
		        current = current.next;
			}
		}
	}
	
	public static void main(String[] args) {
		LinkedListNode head = AssortedMethods.randomLinkedList(10, 0, 10);
		System.out.println(head.printForward());
		deleteDups2(head);
		System.out.println(head.printForward());
	}

}