title: Time complexity of Single Link List Insertion and deletion
body: <p>I am a bit confused about time complexity of Linked Lists. In this article <a href="http://bigocheatsheet.com/" rel="nofollow">here</a> it states that insertion and deletion in a linked list is O(1). I wanted to know how this is possible ? Is it assumed that the forward and next pointers are known ? Wouldn't that  be Double Linked List then ? I would appreciate it if someone could clarify this . And how the time complexity of insertion/deletion of single linked list is O(1) ?</p>