tag: data-structures
articles: 7 · beats: 1
latest: September 1, 2026
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Data Structures
7 Crashtech articles on Data Structures, filed under System Design, published between July 2026 and September 2026. Every piece is full-text HTML with sources, structured data and an authored FAQ.
All 7 sit in the System Design beat. System Design
What Actually Happens Inside a Database Index: The Data Structures
An index trades disk I/O for lookup speed. Here's how B-trees, hash tables, and bitmap indexes each make that trade differently.
Count Billions in 12 Kilobytes
HyperLogLog estimates cardinality by reading leading zeros in hashed values, trading 1% error for fixed memory.
Merkle Trees: How Git Detects Changes in Milliseconds
Git hashes files into nested cryptographic trees to skip unchanged directories in one comparison, finding changes across millions of files faster than scanning.
Bloom Filters: The One-Way Membership Test
A probabilistic data structure: zero false negatives, tunable false positives. Check membership in RAM with bits instead of database queries.
Tries: Why Autocomplete Doesn't Scan Every Word
A trie finds all words with a prefix in O(p) time, independent of dictionary size. Radix compression and top-k heaps make autocomplete instant.
Skip Lists: The Shortcut Nobody Rotates
Balanced trees rebalance with rotations. Skip lists layer express lanes with random promotion—same O(log n) search, simpler locking.
Operational Transforms vs CRDTs
Why Google Docs needs a server and Figma doesn't: how two competing approaches to concurrent editing resolve the same-string conflict, and when each wins.
Questions we answer about Data Structures
- Why does an index's internal data structure matter if it all ends up 'faster than a scan'?
- Why is disk I/O the thing index structures are actually optimizing for?
- Why can't a hash index handle range queries?
- What makes a bitmap index different from a B-tree, and when is it better?
- Why do B-trees stay balanced automatically as data is inserted?
- How does HyperLogLog count unique items without storing them?
- What is the memory cost of HyperLogLog?
- Why use the harmonic mean instead of a simple average?
- When should I use HyperLogLog instead of exact counting?
- Does HyperLogLog work well with merging data from multiple servers?
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Frequently asked questions
What does Crashtech publish about Data Structures?
7 articles tagged Data Structures, the most recent published September 1, 2026. All 7 sit in the System Design beat. Each carries numbered sources, an authored FAQ and full structured data.
What questions about Data Structures does Crashtech answer directly?
10 questions have a dedicated answer page under this tag, including “Why does an index's internal data structure matter if it all ends up 'faster than a scan'?”. Each answer is authored prose from the article it belongs to, not a generated summary.
Can AI assistants read Crashtech's Data Structures coverage?
Yes. Crashtech serves full static HTML to every crawler, allows all major AI user agents in robots.txt, and publishes an llms.txt manifest plus a full-text corpus, so assistants can retrieve and cite these articles directly.