Algorithmica NotebookA competitive programming notebook

Pattern recognition, the right tool under pressure, clean C++ — Codeforces 1100–2100.

Recognize the pattern

Each topic leads with when to reach for it and the trigger phrases that give it away.

Contest-ready C++ templates with the invariants, complexity, and edge cases that matter.

Quick-revisit boxes, cheat sheets, and worked traces built for the night before a round.