Gnit

Gnit is an online contest platform dedicated to physics. Like AtCoder for competitive programming, Gnit offers "competitive physics" — a place to solve physics problems under a time limit. Monitor competitors on the live scoreboard and tackle rigorous physics problems.

Yes, account registration, contest participation, and solving archive problems are all free. Sign up in seconds with email or Google.

Problems span 6 categories: Mechanics, Electromagnetism, Waves, Thermodynamics, Quantum, and Mathematical Physics. Filter by category and difficulty (Beginner to Advanced) on the problem archive page.

All answers are positive integers (≥ 1). Decimals and fractions are not used. For example: "If the speed is 10 m/s, enter 10." Results are displayed instantly and reflected on the scoreboard in real time.

After a contest ends, the mean and standard deviation of all participants’ scores are computed automatically to generate each participant’s score. You can track your score trend in the chart on My Page. Scores are computed per contest, so everyone — from beginner to expert — can see their relative standing.

Yes, problems from finished contests are available on the Problem Archive page anytime. Correct answers accumulate as your archive score, and you can track your accuracy over time on My Page.

We publish solution blog posts with KaTeX-rendered equations. Articles are released progressively after each contest ends, providing clear and detailed explanations.

Each problem has a point value. Solving it correctly adds those points to your total. Ties are broken by "time" (minutes elapsed until your last correct submission plus a 5-minute penalty per wrong answer per problem) — the same system used by AtCoder.

Difficulty is divided into 4 tiers. Lv.1–2 "Beginner" are middle-school physics level. Lv.3–5 "Elementary" are high-school physics and common-test ("kyotsu-test") level. Lv.6–8 "Intermediate" are high-school physics university-entrance-exam level. Lv.9–10 "Advanced" are university physics level.

Let dᵢ be the difficulty (1–10) of each solved problem. The score is: Score = ⌊1000 × log₁₀(10 + Σ 2^dᵢ)⌋. Higher-difficulty problems contribute exponentially more to your score. For example, solving a single difficulty-10 problem alone yields approximately 1308 points.

Yes! You can add Gnit to your home screen and use it like a native app. 📱 iOS (Safari): Tap the Share button (square with upward arrow ↑) at the bottom → "Add to Home Screen" → "Add". 🤖 Android (Chrome): Tap the menu (⋮) in the top-right → "Add to Home Screen" → "Add". An icon will appear on your home screen and you can launch Gnit without any browser UI.