Adds circular list insert at tail, delete head and delete at position…

… k solutions

README.md

@@ -181,7 +181,10 @@ My solutions to competitive programming problems in [Geeks for Geeks](https://au
 |Display circular linked list|[C++](c++/display-circular-linked-list.cpp)|
 |Insert at tail (end) of circular linked list|[C++](c++/insert-tail-circular-linked-list.cpp)|
 |Get length(number of nodes) of a circualr linke list|[C++](c++/get-length-circular-list.cpp)|
+| Delete head of a circular list |[C++](c++/delete-head-of-circular-list.cpp)|
 |Insert at head in a **circular linked list**|[C++](c++/circular-linked-list-head-insert.cpp)|
+|Insert at **end** of a **circular linked list**|[C++](c++/insert-at-the-end-of-circular-linked-list.cpp)|
+|Delete node of Circular list at a specific position|[C++](c++/circular-list-delete-at-position.cpp)|
 |Max and minimum in linked list|[C++](c++/maximum-and-minimum-in-linked-list.cpp)|
 |Delete tail of linked list|[C++](c++/detele-tail-linked-list.cpp)|
 |Search in Linked list|[C++](c++/search-in-linked-list.cpp)|

c++/circular-linked-list-head-insert.cpp

@@ -1,16 +1,25 @@
 // https://practice.geeksforgeeks.org/problems/circular-linked-list-head-insert/1/?track=DSA-Foundation-Final-Circular-Linked-List&batchId=193
+// Time complexity: O(N)
+// Space complexity: O(1)
+/*
+    If we need to optimize this code and do it in
+    O(1) time, we can simply keep stored the updated value of pointer 
+    to the tail node, so that we do not need to iterate every time the 
+    Circular Linked List N times. 
+
+*/
 Node *insertInHead(Node * head, int data)
 {
     Node *new_node = new Node(data);
+    // Corner case: Linked list is empty
     if(head == NULL)
         new_node ->next = new_node;
     else
     {
         Node *current = head;
         while(current->next != head)
-        {
             current = current->next;
-        }
+        // Set last node's next pointing to the new head
         current->next = new_node;
         new_node ->next = head;
     }

c++/circular-list-delete-at-position.cpp

@@ -0,0 +1,23 @@
+// https://practice.geeksforgeeks.org/problems/circular-linked-list-delete-at-position/1/?track=DSA-Foundation-Final-Circular-Linked-List&batchId=193
+
+Node * deleteAtPosition(Node *head,int position)
+{
+    if(head == NULL)
+        return NULL; 
+    // Corner case: the  node to remove is the head 
+    if(position == 1)
+    {
+        return free(head);;
+    }
+    else
+    {
+        Node *current = head;
+        for(int i = 0; i < position-2; i++)
+            current = current ->next;
+
+        Node *temp = current->next;
+        current->next = current->next->next;
+        free(temp);
+        return head; 
+    }
+}

c++/delete-head-of-circular-list.cpp

@@ -0,0 +1,56 @@
+/*
+    Delete head of a circular linked List
+    This implementation is in O(N) time; 
+
+    We can  actually delete the head in O(1) time.
+    To do this operation in O(1) time, we have to:
+    - Store second nodes value to in the head
+    - Delete second node of the linked list
+
+*/
+// O(N) time
+Node * deleteHead(Node *head)
+{
+   if (head == NULL)
+        return NULL;
+   if(head ->next == NULL)
+   {
+       free(head);
+       return NULL;
+   }
+   else
+   {
+       Node *current = head;
+       while(current -> next != head)
+            current = current->next;
+
+        // Set next pointer of the tail to the second node of the linked list
+        current->next = head->next;
+        // Remove original head of the Circular Linked list
+        head->next = NULL;
+        free(head);
+        // Return pointer to the second node of the original linked list(new head);
+        return current->next;
+   }
+}
+
+
+// O(1) Time
+Node * deleteHead(Node *head)
+{
+   if (head == NULL)
+        return NULL;
+   if(head ->next == NULL)
+   {
+       free(head);
+       return NULL;
+   }
+    // Store second nodes value in the head
+    head->data = head->next->data;
+    Node *temp = head->next;
+    head->next = head->next->next;
+
+    // Remove secon node from linked list
+    free(temp);
+    return head; 
+}

c++/insert-at-the-end-of-circular-linked-list.cpp

@@ -0,0 +1,4 @@
+//
+/*
+    De
+*/