Archives

We wrote four hash map implementations, predicted how they'd perform, and declared open addressing the winner. Then we changed the key distribution and watched the winner become 11,000x slower.

I accidentally implemented SPFA while thinking I was doing BFS with relaxation, then had to build a min-heap from scratch before I could do Dijkstra properly.

My first "arena" trie wasn't an arena at all — fixing that revealed real cache locality effects, disassembly surprises, and data-oriented design wins.

Implementing a trie led me into cache effects, const_cast, and what the compiler can and can't optimize away.

A completely opaque data structure turned out to be a flat array of ints with two elegant optimizations — I benchmarked each one to understand what it actually contributes.

How I built a ptrace-based sampling profiler for Linux/AArch64 — what I wrote, what Claude wrote, and where it helped and didn't.

How I completed all 50 stars of Advent of Code 2024 using C++20.

A short post about learning German — written in both German and English.