Removing Duplicate in unsorted list using Hashing

Author: Arunkumarvarada

DataStructures/LinkedList/com/java4u/ds/linkedlist/removeDuplicates/RemoveDuplicates.java

@@ -0,0 +1,59 @@
+package com.java4u.ds.linkedlist.removeDuplicates;
+
+import java.util.HashSet;
+
+import com.java4u.ds.linkedlist.Node;
+
+public class RemoveDuplicatesUsingHashing {
+
+	public Node removeDuplicateInList(Node head) {
+		if (head == null) {
+			return head;
+		}
+		HashSet<Integer> set = new HashSet<>();
+		Node current = head;
+		Node prev = null;
+		while (current != null) {
+			int curval = current.getData();
+			if (set.contains(curval)) {
+				prev.setNext(current.getNext());
+			} else {
+				set.add(curval);
+				prev = current;
+			}
+			current = current.getNext();
+		}
+		return head;
+	}
+
+	static void print(Node head) {
+		while (head != null) {
+			System.out.print(head.data + " ");
+			head = head.next;
+		}
+		System.out.println();
+	}
+
+	public static void main(String[] args) {
+		Node head = new Node(1);
+		Node n1 = new Node(2);
+		Node n2 = new Node(3);
+		Node n3 = new Node(4);
+		Node n4 = new Node(5);
+		Node n5 = new Node(2);
+		Node n6 = new Node(6);
+
+		head.setNext(n1);
+		n1.setNext(n2);
+		n2.setNext(n3);
+		n3.setNext(n4);
+		n4.setNext(n5);
+		n5.setNext(n6);
+		
+		print(head);
+		Node node = new RemoveDuplicatesUsingHashing().removeDuplicateInList(head);
+		print(node);
+
+	}
+
+}