Linked List

This is a premium interview-preparation course on the data structure that separates people who are comfortable with pointers from people who are not. A **linked list** trades O(1) random access for O(1) splicing — you can insert, delete, and rearrange nodes just by rewiring **next** (and **prev**) references, without shifting anything. The catch is that a single dropped pointer loses the rest of the list, so the whole game is manipulating references in the right order. You will start with the mental models (singly, doubly, and circular lists, the fast and slow pointer, and the dummy-node trick that removes edge cases), then work through curated problems grouped by the patterns interviewers actually test: in-place reversal, cycle detection, k-group and pair reversal, merging and sorting, and advanced pointer-heavy design. Every lesson visualises the pointers, dry-runs a concrete example, then shows a clean Java 17 implementation.