Problems
Authored problems and handouts in competitive mathematics and programming.
Mathematics
Programming
Contests currently pending addition: Skot og skil 2026, Forritunarkeppni framhaldsskólanna 2026.
-
Title Year Link Erratic Lights 2025 PDF -
Title Difficulty Year Link Baseball Court 8.9 2024 open.kattis.com Guessing Passwords 8.0 2024 open.kattis.com Hotfix 7.5 2024 open.kattis.com Knitting Pattern 3.7 2024 open.kattis.com Intertwined 9.5 2023 open.kattis.com Keyboard Queries 7.1 2022 open.kattis.com -
Title Difficulty Year Link Chair Game 3.4 - 7.0 2024 open.kattis.com -
Title Difficulty Year Link Compressible Passwords 7.3 2025 open.kattis.com Digital Padlock 8.0 2025 open.kattis.com Factorial Encoding 6.8 2025 open.kattis.com Geofencing 4.4 2025 open.kattis.com Key Management 7.9 2025 open.kattis.com L Keys 8.0 2025 open.kattis.com L33T H4X0R 2.3 2025 open.kattis.com Password Filter 2.1 2025 open.kattis.com Red vs Blue 7.4 2025 open.kattis.com Scream Cipher 4.4 2025 open.kattis.com Server Space 1.6 2025 open.kattis.com Austan Atlantshafs 4.6 2024 open.kattis.com Bjagað Beðaltal 7.5 2024 open.kattis.com Deildadrottnun 3.0 2024 open.kattis.com Einfasa Eindahraðall 7.6 2024 open.kattis.com Fljúgandi Furðuhlutir Forðast Fókus 7.9 2024 open.kattis.com Glötuð Gildi 8.0 2024 open.kattis.com Höskuldarháska 1.8 2024 open.kattis.com Innvolsarinnihaldslýsing 1.7 2024 open.kattis.com Jaðarjuð 7.3 2024 open.kattis.com Lafhræddir Læknar 5.7 2024 open.kattis.com Mergjað Mál 1.6 2024 open.kattis.com Deildajöfnuður 2.0 2023 open.kattis.com Eindahraðall 7.1 2023 open.kattis.com Flæðasmíði 7.2 2023 open.kattis.com Girðingaherping 7.2 2023 open.kattis.com Kaffiskömmtun 7.2 2023 open.kattis.com Majór Skýrsla 3.6 2023 open.kattis.com Spilahlustun 6.4 2023 open.kattis.com Töskupökkun 4.4 2023 open.kattis.com Erfitt dæmi 5.2 2022 open.kattis.com Gagnageymsla 4.6 2022 open.kattis.com Neumann 1.6 2022 open.kattis.com Rommí 6.1 2022 open.kattis.com Tvö göng 7.0 2022 open.kattis.com Epsilonþraut 5.8 2021 open.kattis.com Hroglamál 2.4 2021 open.kattis.com Húsatengingar 6.7 2021 open.kattis.com Næstbest 7.9 2021 open.kattis.com Ný mylla 7.0 2021 open.kattis.com Tilefni 5.6 2021 open.kattis.com Vegaframkvæmdir 5.8 2021 open.kattis.com Flygildaflug 4.6 2020 open.kattis.com Innstunguvesen 7.9 2020 open.kattis.com Mengi 2.0 2020 open.kattis.com Mynstursmisskilningur 6.8 2020 open.kattis.com Neðanjarðargöng 8.7 2020 open.kattis.com Strengjafræði 5.7 2020 open.kattis.com Vinabönd 3.5 2020 open.kattis.com Dulmál 6.7 2019 open.kattis.com Fundir 6.7 2019 open.kattis.com Hola Íslenskra Fræða 4.3 2019 open.kattis.com Húsahlaup 4.6 2019 open.kattis.com Kaffi 5.5 2019 open.kattis.com Lög 2.5 2019 open.kattis.com Reiknirit 4.8 2019 open.kattis.com Sunnlenska 3.4 2019 open.kattis.com Vittu betur 4.8 2019 open.kattis.com Völundarhús 6.3 2019 open.kattis.com -
Title Difficulty Year Link ASCII Box 3 3.6 - 4.9 2025 open.kattis.com Calculator 4.5 - 7.8 2025 open.kattis.com Cards Sorting 1.3 - 1.6 2025 open.kattis.com Colour Analysis 1.3 - 1.7 2025 open.kattis.com Concatenate 1.1 2025 open.kattis.com Contrarianism 1.4 2025 open.kattis.com Darts Scoring 1.9 - 2.9 2025 open.kattis.com Diggy Hole 1.3 2025 open.kattis.com EIEIO 2.6 2025 open.kattis.com Electric Torch 2.5 - 7.9 2025 open.kattis.com Enjoy Your Repast! 1.1 2025 open.kattis.com File Extension 1.2 - 1.4 2025 open.kattis.com Homework Workload 3.2 - 7.8 2025 open.kattis.com Inputmaxxing 1.3 - 4.0 2025 open.kattis.com Láki 2.1 - 7.9 2025 open.kattis.com Magnificent Noughts & Crosses 3.3 - 7.0 2025 open.kattis.com Pathfinder 2.9 - 4.6 2025 open.kattis.com Pigeon-holes 1.6 2025 open.kattis.com Press-ups 2.1 - 7.8 2025 open.kattis.com Radicalists 2.1 - 4.9 2025 open.kattis.com RedTok ShortReels 2.7 - 8.1 2025 open.kattis.com Soviet Union-Find 2.6 - 4.8 2025 open.kattis.com Steam Column 1.6 2025 open.kattis.com Supervisor 2.2 - 5.8 2025 open.kattis.com Touch Grass 1.5 2025 open.kattis.com Traffic Lights 5.2 - 6.9 2025 open.kattis.com Type Faster 4.5 - 5.6 2025 open.kattis.com Web Page 1.3 - 2.4 2025 open.kattis.com ASCII Kassi 2 2.3 - 2.4 2024 open.kattis.com Aflmælingar 3.2 - 5.7 2024 open.kattis.com Draga Frá 1.1 2024 open.kattis.com Enn Eitt EEEE Erfiði 1.5 - 7.3 2024 open.kattis.com Ferskasta Jarmið 1.7 - 1.9 2024 open.kattis.com Flugvallakóðar 1.4 - 7.2 2024 open.kattis.com Golf 1.3 - 4.4 2024 open.kattis.com Hnappasetningaskipti 1.4 - 2.1 2024 open.kattis.com Höfundaleit 1.3 - 2.0 2024 open.kattis.com Liðaskipting 2 1.4 - 2.4 2024 open.kattis.com Ríkjafræði 2 2.4 - 6.6 2024 open.kattis.com Rúnnfræði 5.7 - 7.9 2024 open.kattis.com Taktsveðjur 1.3 - 2.9 2024 open.kattis.com Tarot Póker 6.8 - 7.3 2024 open.kattis.com Töskuröðun 1.8 - 4.9 2024 open.kattis.com Ævintýraröð 2.7 - 3.3 2024 open.kattis.com Manhattanstíflur 4.2 - 6.5 2023 open.kattis.com Skattmann 4.5 - 9.7 2023 open.kattis.com Tónlistarlisti 3.4 - 5.2 2023 open.kattis.com Þarasöfnun 2.0 - 8.1 2023 open.kattis.com Ekki dauði opna inni 1.4 - 1.5 2022 open.kattis.com Matarinnkaup 1.5 - 3.6 2022 open.kattis.com Níulegasti grunnurinn 4.5 - 8.0 2022 open.kattis.com Ríkjafræði 3.5 - 3.8 2022 open.kattis.com Samlokur 3.6 - 4.7 2022 open.kattis.com Tvær Vikur 3.0 - 4.6 2022 open.kattis.com Viðnámsflækja 3.1 - 4.8 2022 open.kattis.com Hringvegurinn 2.7 - 4.3 2021 open.kattis.com Röðunarrugl 1.7 - 2.4 2021 open.kattis.com Teningakast 4.2 - 8.1 2021 open.kattis.com Teningasafn 3.2 - 6.1 2021 open.kattis.com RNG Test 1.4 - 5.9 2020 open.kattis.com Veður 2.4 - 4.3 2020 open.kattis.com -
Title Difficulty Link Any Pythagorean Triple 2.1 open.kattis.com Big Factoring 7.5 open.kattis.com Consecutive Prime Sums 4.1 open.kattis.com Divisors of a sum 4.8 open.kattis.com Double Palindromes 4.7 open.kattis.com Largest Factor 2.3 open.kattis.com Longest Collatz Chain 2.8 open.kattis.com Sums of Primes 3.0 open.kattis.com Threes and Fives 4.3 open.kattis.com Trailing Digits 3.1 open.kattis.com Pole Colouring 2.9 open.kattis.com Royal Routing 4.6 open.kattis.com State Transfer Matrix 3.5 open.kattis.com Wider Digbuild 4.3 open.kattis.com All Modulo Pythagorean 5.7 open.kattis.com All Pair Sums 6.2 open.kattis.com Dice Results 6.8 open.kattis.com Fast Fourier Transform 3.2 open.kattis.com Naïve Convolution 3.1 open.kattis.com Number Theoretic Transform 5.1 open.kattis.com Orthogonal Rotation 6.0 open.kattis.com Primitive Roots 6.7 open.kattis.com Green Hackenbush 6.4 open.kattis.com Hackenbush Bamboo 2.0 open.kattis.com Hackenbush Lupines 6.8 open.kattis.com Hackenbush Purplehearts 4.6 open.kattis.com Hackenbush Shrubbery 4.8 open.kattis.com Hackenbush Simplicity 7.5 open.kattis.com Red/Blue Hackenbush 5.4 open.kattis.com All Square Sums 6.2 open.kattis.com Almost Pythagorean 7.2 open.kattis.com Binary Exponentiation 3.2 open.kattis.com Brahmagupta-Fibonacci 3.1 open.kattis.com Early Termination 3.3 open.kattis.com Euclid's Algorithm 1.6 open.kattis.com Gauss Squares 4.3 open.kattis.com Root of Minus One 4.6 open.kattis.com Avoiding Subsequence 3.6 open.kattis.com Naïve Quotient 5.6 open.kattis.com Powerbonacci 6.6 open.kattis.com Starbonacci 6.1 open.kattis.com -
Title Difficulty Year Link Av(1324) 2.4 - 7.5 2023 open.kattis.com Hópavinna 2.5 - 3.2 2023 open.kattis.com Koffínhraði 1.3 - 1.8 2023 open.kattis.com Námsleið 1.6 - 2.0 2023 open.kattis.com Vinnuálag 3.3 - 3.9 2023 open.kattis.com -
Title Difficulty Link Bank Closing 2.3 open.kattis.com Botched Sequence of Tyrfingur 4.5 open.kattis.com Einkaþjálfari 1.7 - 3.8 open.kattis.com Split Median 3.4 - 9.4 open.kattis.com Vacation Space 2.4 open.kattis.com -
Title Difficulty Link Job Qualifications 2.6 open.kattis.com -
Title Difficulty Year Link Fimbulferð 6.6 2023 open.kattis.com Fjallamynstur 6.1 2023 open.kattis.com Fjölmenni 3.7 2023 open.kattis.com Flatarreikningar 2.0 2023 open.kattis.com Flottar tölur 6.1 2023 open.kattis.com Framhjá Polli 5.9 2023 open.kattis.com Fylking hæða 7.9 2023 open.kattis.com Bruni Íslenskra Fræða 8.6 2023 open.kattis.com Diffrun 7.1 2023 open.kattis.com Höfundanöfn 2.7 2023 open.kattis.com Upp og niður 8.3 2023 open.kattis.com Yet Another Query On Array Problem 6.6 2023 open.kattis.com Bíórugl 4.3 2022 open.kattis.com DCC líkur 2.7 2022 open.kattis.com Leiðinda rigning 6.5 2022 open.kattis.com Skálagerð 1.6 2022 open.kattis.com Vatnskubbur 8.0 2022 open.kattis.com Baba Yaga 3.5 2022 open.kattis.com Bastard's Peace 5.6 2022 open.kattis.com Becquerel 64 3.3 2022 open.kattis.com Beelining 7.0 2022 open.kattis.com Blimps Fort Barricade 3.3 2022 open.kattis.com Braincutter's Association 5.6 2022 open.kattis.com Buck Hunt 1.6 2022 open.kattis.com A Night To Remember 8.4 2020 open.kattis.com Bogletics Intermission 2.8 2020 open.kattis.com Conundrum on the Roof 3.4 2020 open.kattis.com Down To Factor 3.5 2020 open.kattis.com Fjord's 42 4.8 2020 open.kattis.com Grand Combat Delusion: The Movie 5.6 2020 open.kattis.com Hydrationsword Saga 7.2 2020 open.kattis.com Gaiaria 6.0 2020 open.kattis.com Grand Combat Delusion 4.2 2020 open.kattis.com HKIO 4.6 2020 open.kattis.com Splay the Sire 4.8 2020 open.kattis.com Tilde City 5.6 2020 open.kattis.com Association of Myths 4.2 2019 open.kattis.com Digbuild 3.9 2019 open.kattis.com Geezer Scripts 2.6 2019 open.kattis.com Planetaris 1.7 2019 open.kattis.com Striker-Count 3.9 2019 open.kattis.com Tildes 2.3 2019 open.kattis.com