Here is an amazing snapshot of a programming competency matrix at different levels: Computer Science 2 n (Level 0) n 2 (Level 1) n (Level 2) log(n) (Level 3) data structures Doesn't know the difference between Array and LinkedList Able to explain and use Arrays, LinkedLists, Dictionaries etc in practical programming tasks Knows space and time tradeoffs of the basic data structures, Arrays vs LinkedLists, Able to explain how hashtables can be implemented and can handle collisions, Priority queues and ways to implement them etc. Knowledge of advanced data structures like B-trees, binomial and fibonacci heaps, AVL/Red Black trees, Splay Trees, Skip Lists, tries etc. algorithms Unable to find the average of numbers in an array (It's hard to believe but I've interviewed such candidates) Basic sorting, searching and data structure traversal and retrieval algorithms Tree, Graph, simple greedy and divide and conquer algorithms, is able to understand the relevance of