sorting

A three-minute capture of SORTDEMO.BAS, the sorting visualization that shipped with QBasic. It animates insertion, bubble, heap, exchange, shell and quick sort with chiptune-like sound.

Dave Ackley demonstrates the Demon Horde Sort, an inherently robust sorting machine running in his Movable Feast Machine simulator. This is the uncut version with all details and side thoughts.

Dave Ackley gives a high-level introduction to robust-first computing, which prioritizes robustness over efficiency in computer architecture. A sorting demo illustrates the idea.

Juan Pedro Bolivar Puente explains immutable and persistent data structures in C++ and how they support value semantics. He presents the Immer library, rrb-trees, and a prototype text editor that opens a huge file instantly.

Donald Knuth's 2017 Christmas Tree Lecture at Stanford about a combinatorial geometry problem whose computed numbers matched a striking formula. He tells the story of the conjecture and its sequel.

A 2007 Google Tech Talk in which Cliff Click of Azul Systems presents a lock-free concurrent hash table that scales to 768 CPUs. He explains why it is correct by reasoning in a different way than usual happens-before and memory-order arguments.

A Dyalog demonstration of developing a Sudoku solver in APL, using an algorithm by Arthur Whitney with performance work by John Scholes. The narration steps through the array-oriented solution.

James Long's dotJS 2019 talk on how CRDTs enable local-first apps and how simple they can be to implement. He shows how to use them to build robust offline-capable frontends.

Guy Steele presents a small geometric problem and compares four computational approaches: a classic sequential solution and three parallel-friendly ones. Each is illustrated pictorially and with working code, weighing total work against time to solution.

Martin Kleppmann's QCon London 2018 talk on keeping data consistent in distributed systems without a central leader. It surveys CRDT algorithms for syncing devices and collaborative editing over peer-to-peer networks.

John Scholes builds a depth-first tree-search operator step by step in a Dyalog APL session. It covers higher-order functions and runs the search on the N-Queens problem.

A JSConf 2014 talk visually breaking down algorithms behind everyday UI patterns, such as dropdown menus that vanish when the mouse drifts and picking the nearest target to the cursor. It shows how these are implemented in JavaScript.

Redis Labs and Tim Davis present RedisGraph, which uses GraphBLAS to treat graph queries in Cypher as sparse linear algebra for lower latency.

Stephan T. Lavavej's CppCon 2019 talk on implementing floating-point to_chars and from_chars in Microsoft's C++ STL. It covers the history of float-string conversion and the algorithms that make it much faster.

Elasticsearch engineer and Lucene committer Adrien Grand explains the design decisions inside a Lucene index and what problems it can and cannot solve. The talk goes into how Lucene stores data for fast search and analytics.

Martin Kleppmann surveys current research on CRDTs, the algorithms for merging concurrent edits across offline replicas. He covers the hard parts such as rich text, moves and merge results that are technically correct but poor.

Erik Demaine's MIT 6.851 Advanced Data Structures lecture introducing succinct data structures, covering rank, select and tries. It is part of the Spring 2012 course.

Bryan Cantrill presents the ARC (Adaptive Replacement Cache) paper by Megiddo and Modha at Papers We Love. He opens with a survey of caching strategies before digging into the self-tuning LRU/MFU design.

Neil Fraser of Google presents Differential Synchronization, the algorithm behind MobWrite, for keeping multiple copies of a document in sync in real time. The talk argues the approach is robust, convergent and efficient.

Aaron Hsu shows how to manipulate and transform tree data in APL using arrays and inverted tables instead of pointers. He claims much smaller code, better performance and easier parallelisation.

Daniel Lemire's QCon talk on how simdjson parses gigabytes of JSON per second. It covers SIMD vectorization, branch prediction and the lessons learned building a fast parser.

Matt Kulukundis reviews two years of Abseil's Swiss table hashtable, covering post-release optimizations, lessons from rolling it out across Google, design choices, and what global monitoring revealed.

Malte Skarupke's C++Now 2018 talk on hash table performance, explaining why std::unordered_map is slow and memory hungry and presenting faster designs, including his bytell hash map.

Jon Bentley walks through three implementations of Hoare's Quicksort, from a dozen-line C function to a series of systematic code transformations that make the program ever simpler and more powerful. It is a Google Tech Talk on code elegance and program derivation.

A Microsoft Research talk on BetrFS, a file system built on B-epsilon trees, a write-optimized data structure. It covers WODS such as LSM-trees, how to design a file system around them, and benchmark wins over ext4 and xfs.

Andrei Alexandrescu's ACCU 2016 talk previews material from his book on writing fast code, with a focus on optimization techniques such as sentinels and faster search.

Edward Kmett's 2013 talk at Prezi in Budapest on succinct data structures, which store data in close to the information-theoretic minimum space while supporting fast queries. It ties together the research and walks through his Haskell succinct library.

Find the Longest Path is a comedic song by Daniel J. Barrett, a Billy Joel parody that describes the NP-hard longest path problem in informal terms.

Uber Engineering's Joseph Gilley explains why Uber uses hexagons for geospatial indexing and introduces H3, its open source hierarchical grid system. He covers use cases and how distortion is handled.

A one-minute clip of Peter Norvig saying that Google found programming contest success correlates negatively or poorly with job performance. The description links to a blog post discussing it.