Adding Remove_Duplicates_from_Unsorted_Doubly_LL.c++

Lecture048 Linked List Day5/removeDuplicatesfromUnsortedDoublyLL.c++

@@ -0,0 +1,44 @@
+#include <bits/stdc++.h> 
+/****************************************************************
+    Following is the class structure of the Node class:
+    class Node
+    {
+    public:
+        int data;
+        Node *next;
+        Node(int data)
+        {
+            this->data = data;
+            this->next = NULL;
+        }
+    };
+*****************************************************************/
+
+// Problem Link-> https://shorturl.at/15bsG    
+/* Complexity Analysis:-
+Time Complexity: O(N), where nn is the number of nodes in the linked list.
+Space Complexity: O(N), primarily due to the space used by the hash map to store unique node values.
+*/
+
+
+Node *removeDuplicates(Node *head)
+{
+    // Write your code here.
+    Node* currentNode = head;
+    Node* prevNode = NULL;
+    unordered_map<int, bool> visitedNode;
+
+    while(currentNode != NULL) {
+        if (!visitedNode[currentNode->data]) {
+            visitedNode[currentNode->data] = true;
+            prevNode = currentNode;
+            currentNode = currentNode->next;
+        }
+        else {
+            prevNode->next = currentNode->next;
+            free(currentNode);
+        }
+        currentNode = prevNode->next;
+    }
+    return head;
+}