A daily complexity-recognition drill
Bugdle Big-O is a daily complexity-recognition puzzle. Each day you get a short, plain-language snippet — usually 4–15 lines of code in Python, JavaScript, Go, Rust, Java, or C++ — and four attempts to name its dominant time complexity from a fixed ladder: O(1), O(log n), O(n), O(n log n), O(n²), O(n³), O(2ⁿ), O(n!). Every wrong guess returns a directional hint — “too high” or “too low” — which turns the puzzle into a tight binary-search exercise on top of the underlying reading task.
Most working engineers can produce a complexity analysis when asked, but few practice the reverse: looking at unfamiliar code and judging its growth at a glance. That instinct is exactly what code review, performance triage, and on-call incidents reward. The post-solve postmortem explains why each puzzle lands on the rung it does — including the classic confusables (a nested loop whose inner bound is a constant; a recursion that looks exponential until you memoise it; an amortised data-structure operation that averages cheaper than its worst case).
Big-O is one of six daily Bugdle puzzles. The others are the full bug puzzle, Spotlight, Connectle, Framed, and Algodle.