HashLab — Interactive Data-Structure Visualizer Built Around Modern Hash Tables
An app that turns the internals of hash tables — buckets, overflow chains, Swiss Table groups, probe sequences, cache lines — into animations students can poke, break, and rebuild, so the theory from a Go runtime post actually sticks.
undergraduate CS students taking data structures and algorithms
- Side-by-side Swiss Table vs. classic bucket animation with adjustable load factor and hash function
- Step-through probe inspector that highlights fingerprint checks, key comparisons, and cache-line hits/misses
- Quiz mode that asks the student to predict the next probe step or the resulting cluster shape
- Exportable lab sheets instructors can drop into a course site
Go 1.24's switch to Swiss Tables has pushed hash-table internals back into CS coursework and interview prep, and current visualizers like VisuAlgo haven't been updated to show the new design.
Go's official Swiss Tables blog (Feb 2025) and multiple derivative posts exist, but the cited HN thread had only 15 points/0 comments and Swiss Tables remains niche vs. classic chaining/linear-probing taught in most curricula.Faster Go maps with Swiss Tables - The Go Programming Language ↗Go 1.24 uses Swiss Tables, what are they? - DEV Community ↗
At least 5 free hash-table visualizers already exist (basicfreetools, computersciencesimplified, dsanotes, dsavisualization, visualgorithm) plus VisuAlgo and Algorithm-Visualizer; the Swiss-Table-specific angle is the only true gap, and it's narrow.Hash Table Visualizer -- Watch Hashing, Collisions, and Probing Animate ↗Hash Table Visualizer - Hashing & Collisions | CS Simplified ↗
Adjacent paid tools like Expora target interview prep with broader scope; pure DS-course visualizers struggle against free incumbents (VisuAlgo, Algorithm-Visualizer) and undergrads are price-sensitive — plausible only via institutional/bundle licensing.Expora — Visual Algorithm Debugger for Coding Interviews ↗Best Algorithm Visualizer for Interviews 2026 | Expora Blog ↗
Hash tables are a permanent fixture of CS curricula and Swiss Tables are now adopted by Go, C++ (Abseil), and Rust (hashbrown) — multi-language trend, very durable.Faster Go maps with Swiss Tables - The Go Programming Language ↗
Pure frontend animation of well-defined data structures (groups, control bytes, probe sequences) using standard web tech (Canvas/SVG/D3) — no exotic infra, modest engineering scope.Algorithm Visualizer ↗