Learn Data Structures & Algorithms

Interactive, animated walkthroughs: pick an operation, press Run, and step through exactly what happens, with Java code for each.

Data structures

ArrayContiguous, indexed memory: instant reads, costly inserts.Linked ListNodes chained by pointers: cheap inserts, no random access.StackLast in, first out: undo history and call stacks.QueueFirst in, first out: job queues and print spoolers.Hash TableKeys hashed into buckets for O(1) lookups.Binary Search TreeAn ordered tree: fast search and sorted traversal.

Algorithms

Binary SearchHalve a sorted array until you find the target.SortingEleven sorting algorithms, animated step by step.

Reference

HTTP Status CodesWhat every status code means and how to fix it.