Here is a list of all the Open Kattis problems I have solved. There is also another version of this page, at a secret URL, where I have tagged each problem with key words relating to its solution. Send me an email if you would like access.

You can sort problems by name, grade, or difficulty by clicking on the appropriate heading.

Here is an explanation of my grading system, which is intended to give a rough indication of what level of background knowledge is needed to solve a given problem (independent of its difficulty).

ProblemGradeDifficulty
10 Kinds of People C/14.6
2048 A+/02.9
So you want to be a 2^n-aire? A/33.1
3D Printed Statues A/12.8
4 thought B/03.2
Eight Queens B/02.8
99 Problems A/02.9
99 Problems C+/01.2 - 5.8
A1 Paper A/14.2
Aaah! A/01.5
Abandoned Animal C-/05.2
ABC B/02.0
ABC String A+/05.5
Ab Initio D/06.8
Above Average A/12.1
Absolutely Symmetric A/04.1
Abstract Art E/36.7
Abstract Painting A/2+4.2
Absurdistan Roads II C/36.9
Absurdistan Roads III D/05.8
A Cappella Recording B/03.1
Access Denied A/04.1
Access Points B+/35.9
Ace Arbiter A/04.9
ACM Contest Scoring A/01.9
Association for Computing Machinery A/12.7
The Calculus of Ada C/12.4
Add 'Em Up! B+/27.2
Adding Trouble A/01.3
Adding Words B+/03.8
Add Two Numbers A/01.3
Adjoin the Networks D/15.7
Administrative Difficulties B/05.7
Adolescent Architecture A/14.3
Ads C/04.9
Adventures in Moving -- Part IV C/05.3
Ævintýraröð A/1+3.2 - 4.7
Afjörmun A/01.4 - 1.6
Agamemnon's Odyssey C/04.8
AI Jeopardy B/26.3
Air Conditioned Minions D/03.2
Airline Hub A/36.5
Akcija B/01.9
Alchemy 101 A/24.0
Aldursröðun B/12.3 - 2.7
Alehouse D/13.9
Á leið í bíó A/01.1
Alex and Barb A/23.6
Alice in the Digital World A+/04.2
Alien Integers A/15.9
Alien Math B/12.5
Alien Numbers A/22.5
All about that base A/22.7
All Different Directions B/22.7
All is Well D/17.0
Alloys A/13.7
All Pairs Shortest Path D/05.0
Almost Perfect A/3-3.0
Almost Union-Find D+/07.2
Alphabet B/03.1
Alphabet Animals B/03.5
Alphabet Spam A/01.7
Alto Singing A/25.6
Amanda Lounges C/05.8
A Mazing! C/05.5
Amerískur vinnustaður A/01.3
Sheba's Amoebas C-/01.8
Amsterdam Distance A/12.6
A Multiplication Game A/24.4
Anagram Counting B/22.8
Andrew the Ant B-/25.0
A New Alphabet A/02.3
Anime Shops C+/03.8 - 6.5
Alternative Anagram B/15.3
Annoyed Coworkers B/13.5
Another Brick in the Wall A/12.4
Another Candies A/12.6
Antenna Placement D/04.4
Anthony and Cora C/24.8
Anthony and Diablo A/12.8
Ocean's Anti-11 A/22.4
Ocean's Anti-11 (Hard) E/27.6
Antiarithmetic? A/36.8
Anti-Palindrome A/01.9
Ants A/12.3
Ant Typing E/26.2
Apaxiaaaaaaaaaaaans! A/01.5
Honour Thy (Apaxian) Parent A/01.8
Aperiodic Appointments A/26.7
A Pivotal Question B/04.6
A+B Problem E/36.4
Appalling Architecture A/14.1
Appeal to the Audience C/05.3
The Apple Game E/27.9 - 8.7
Falling Apples A+/03.3
Johnny Applesack C/13.2
A Prize No One Can Win B/03.2
Aqueduct Construction E/17.0
Arachnophobia D/05.1
Arbitrage? D/13.8
Architecture A/02.8
Arctic Network D-/03.3
A Real Challenge A/12.2
Are You Listening? B/12.7
Arithmetic A/23.1
Arithmetic Decoding B/22.4
ARMPIT Computations C/12.9
Army Strength (Easy) A/02.3
Army Strength (Hard) A/02.2
Array of Discord A/04.6
Array Smoothening A/01.1 - 3.2
Arriving on Time C/04.7
Amalgamated Artichokes A/1+2.4
Artwork C/25.8
ASCII Addition A/02.5
ASCII Figure Rotation A+/03.3
ASCII kassi A/01.3 - 1.5
ASCII Kassi 2 A/02.0 - 2.1
Ask Marilyn A/24.1
Assassins C/26.8
Association of Myths A/24.5
Associative Exponents A/23.7
Asteroid Avoidance A/12.9
Asteroid Mining E/07.8
Astro A/34.1
Astrological Sign A/02.5
Atlögur A/02.2
Attendance A/01.8
Austan Atlantshafs C/05.2
Autori A/01.2
Average Character A/01.9
Paradox With Averages A/12.8
Paradox With Averages (Hard) A/13.1
Average Speed A/13.4
Avion A/01.4
AVL++ C/35.7
Avogadro A+/06.0
Avoiding the Abyss A/02.8
Avoidland A/23.0
Awkward Party B/02.4
BAAS C/05.1
Babelfish B/02.6
Baby Bites A/01.8
Babylonian Numbers A/22.0
Baby Names B+/05.6
Baby Panda A/12.3
Bachet's Game C/23.8
Backpack Buddies D/16.6
Backspace B/01.9
Bacon, Eggs, and Spam B/02.0
Bag of Tiles D/25.7
Balanced Diet C/03.1
Balanced Tree Path C/07.5
Ball B/02.3 - 4.0
Ball Bearings B/1+4.1
Ball Colors A/36.5
Distributing Ballot Boxes B+/14.2
Balls and Needles C/04.0
Baloni C/03.8
Banana Problem B+/16.3
Bank Queue B/02.7
Bannorð B/01.4 - 1.6
Barcelona A/01.3
Bar Classification B/04.1
Barcode B/36.8
Bard B/02.5
Barica C+/06.2
Bar Shelf E/01.4 - 6.8
Base-2 Palindromes A/24.3
basic E/18.3
BASIC Interpreter E/05.3
Basic Programming 1 A+/01.2 - 4.9
Basic Programming 2 B/01.2 - 4.0
Basic Remains A/13.5
Basketball One-on-One A/01.5
Batmanacci B/33.0
Exploding Batteries C/04.1
Batter Up A/11.4
Battle of Hogwarts D/05.5
Battleship C/04.7
Battle Simulation A/02.4
Baza B+/05.8
Bazen A/1+2.6
Beast Bullies A+/05.8
Beat the Spread! A/12.2
Beautiful Primes A/24.0
Beautiful Square A/07.1
Beavergnaw A/11.7
Beehives A/12.2
Beehives D/05.2
Bee House Perimeter C/33.7
Beekeeper A/02.5
Collecting Beepers C/04.2
Bee Problem C/34.2
Bela A/01.4
Bell Ringing A/34.6
BergMál A/01.2
Bergur A/01.8 - 2.0
Berry Battle C+/05.1
Besta gjöfin A/01.2 - 1.3
Best Before A/13.8
Best Compression Ever A/22.5
Best Rational Approximation A/35.1
Best Relay Team B/01.6
Betting A/01.3
Bicikli C/06.6
Bið, endalaus bið A/01.4 - 2.5
Bidirectional Code A/17.2
Big Boxes B/02.8
The Biggest Triangle A/34.6
Big Totoro A/13.2
Big Truck C+/03.1
Bijele A/01.3
Bike Gears B/14.9
Bikes and Barricades A/12.2
Bilað Lyklaborð A/01.5
Bilateral Projects C/06.7
Billiard A/12.2
Bílskúrar C/11.5 - 2.5
Bing It On B/02.8
Bíóferð C+/02.7 - 6.0
Bíókort B/11.4 - 3.9
Bio Trip D/17.1
Bird Rescue D/15.4
Birds on a Wire A/1+2.9
Birthday Party D/02.8
Birthday Boy B/14.7
Birthday Paradox A/35.4
Bishops A/22.3
Bit 4 Bit D/07.9
Bit by Bit A/23.2
Bitmask A/03.5
Bits B/12.4
Bits Equalizer A/23.9
Bitte ein Bit A/01.3
BizzFuzz A/11.9 - 4.4
Black Friday B/02.2
Black Out A/23.2
Blaðra B/01.7 - 1.8
Blaðra A/01.2
Blandað Best A/01.2
Block Crusher C/13.5
Block Game A/23.7
Blocks on Blocks E/36.4
Bluetooth A/01.4 - 2.0
Boat Parts B/02.1
Bobby's Bet A/32.6
Bocchi's Rocks B/01.5 - 3.4
Boggle B/04.7
Accounting B/04.1
Bond E/26.0
Book Circle D/05.2
Book Club C/04.7
Booking D/15.3
Booking a Room B/01.8
Bootstrapping Number B/02.8
Borders D/06.8
The Stock Market C/02.5 - 3.4
Boss Battle A/12.0
Bottled-Up Feelings A+/32.4
Bottle Flip B/12.3
Curvy Little Bottles B/32.9
Bounding Box A/34.5
Bounding Robots A/22.0
Bowser's Pipes C/05.8
Boxes D/03.4
Bracket Matching B/02.0
Alternative Bracket Notation C/05.2
Bracket Pairing C/06.2
Bracket Sequence B+/05.2
The Board Game D/03.8 - 3.9
Bread Sorting A/34.3
Bread Pit C+/16.7
Breaking Bad C/03.2
Breaking Branches A/01.6
Breaking Cake C/05.7
Letter Optimization C/01.3 - 5.0
Brexit C/03.0
Brexit Negotiations D/05.1
Bridges and Tunnels C/02.7
Brocard Point of a Triangle D/34.7
Broken Calculator A/02.7
Broken Keypad A+/0+5.1
Broken Swords A/12.0
Brownie Points I B/12.2
Brýr D/01.5 - 2.5
Binary search tree B+/07.5
Delicious Bubble Tea A/12.6
Bucket Brigade A/13.9
Build Dependencies C/04.1
Building Boundaries A/13.8
Building Highways A/01.2 - 2.0
Buka A/01.9
Bumped! D/04.4
Bungee Builder A+/03.5
Bungee Jumping A/34.7
Burizon Fort B/24.8
Burrows-Wheeler E/05.8
Bus A/11.7
Bus Lines A/12.3
Bus Numbers A/02.2
Bus Numbers B/12.7
The Bus Card A/11.3 - 3.0
Bus Ticket C/14.5
Busy Roads C/13.4
Busy Schedule A/12.3
Button Bashing C/13.3
Buzzwords E/05.1
Cake A+/04.9
Cakey McCakeFace B+/04.5
Calculating Dart Scores B/02.6
Calculator E/02.9
Call for Problems A/01.3
Calories From Fat A+/13.1
Camp Lunches C/14.8
Canadians, eh? A/01.6
Candle Box A/22.7
Candy Distribution A/33.8
Candy Division B/32.9
Candy Store B/01.4
Cangaroo C+/04.5
Canonical Coin Systems D/04.9
Cantina of Babel D/13.0
Cantor A/22.9
Canvas Painting E/03.9
Canvas Line A+/05.1
Canyon Crossing D/06.3
Cardboard Container A/22.4
Card Counting Club B/05.5
Card Divisibility A/24.0
Card Hand Sorting D/04.6
Card Hands B/06.3
Card Magic C/13.4
Card Trading B/02.3
Card Trick B/02.1
Careful Ascent A/12.1
Carnival General B+/01.2 - 3.9
Carousel Rides B/12.4
Solving for Carrots A/01.3
Car Trouble C/04.4
Car Vet C/03.9
Cash Transport B+/07.2
Catalan Numbers A/23.4
Catalan Square A/23.2
Catching Noodles C+/26.5
Catenyms D/06.8
A Feast For Cats C/03.6
Cat vs. Dog C+/05.9
Advanced Causal Measurements E/27.2
Cave Exploration D/03.2
Cave Exploration C/03.9
CD B/03.6
CDVII B/06.3
Ceiling Function B/02.2
Cent Savings D/14.8
Opening Ceremony B/13.3
Cetiri A/11.7
Cetvrta A/01.4
Chair Hopping A/35.3
Champernowne Count A/13.7
Champernowne Verification A/01.5
Chanukah Challenge A/11.3
Character Development A/22.3
Charged A/12.3
Charles in Charge C/05.0
Charting Progress B/02.1
Chatter C/04.0
Cheating at War E/05.5
Cheating a Boolean Tree D/03.9
Checking Break A+/26.1
Checking For Correctness A/23.8
Checkmate in One A/04.4
Cutting Cheese B+/12.9
Cheese, If You Please E/13.5
Chemist's vows E/03.1
Chess A/23.2
Chess Competition D/06.4
Chess Tournament C/05.6
Chewbacca B/23.0
Chili COM Carne A/13.9
Chinese Remainder A/34.2
Chocolate Division A+/01.8
Preludes A/01.9
Chopping Wood B/33.1
Chugging A/01.6
Cinema Crowds A/02.1
Cinema Crowds 2 A/01.8
Cinema Seating B/02.7
Circuit Math B/02.1
Circular DNA C/13.4
Circular Caramel Cookie B/14.0
Circumsphere A/35.2
The Citrus Intern C/13.6
Class Picture B+/04.8
A Classy Problem B/04.6
Cleaning Pipes E/25.3
Climbing Stairs A/14.4
Climbing Worm A/22.3
Clinic B+/14.0
Clock Construction B/04.2
Clock Pictures E/13.7
Closest Pair (Uniform) E/24.6
Closest Sums B/12.7
Closing the Loop A/12.1
Coast Length C/02.9
A Furious Cocktail A/02.8
Cocoa Coalition A/24.8
Coconut Splat B/01.6
Code Cleanups A/13.7
Code Guessing A/03.0
Code Names D/35.3
Codes A/25.7
Code to Save Lives A/11.6
Coffee Cup Combo A/01.5
Coffee Date D/25.0
Coin Stacks B/03.6
Cokolada A/22.2
Cold-puter Science A/01.3
Collapse C/03.3
Collatz Conjecture A/13.8
Collatz Conjecture D/26.9
Coloring Socks B/12.0
Coloring Graphs B+/05.3
Colorland A+/03.7
Colourful New World C/05.4
Colour Wars B/02.7
Prof. Fumblemore and the Collatz Conjecture A/14.9
Combination Lock A/22.9
Combinatorial Stanley Cup A/23.0
Comma Sprinkler C/04.5
Radio Commercials B/01.9
Committee Assignment E/37.2
Common Factors A/34.6
Jumbled Communication A/12.1
Communication Line A/03.3
Communications Satellite C/23.6
Jumbled Compass A/12.0
Competitive Arcade Basketball B/02.1
Completing the Square A/22.1
Composed Rhythms A/01.4
Compositions C/12.3
Compound Words A/01.9
Compression A/04.4
Best Compromise A/12.0
Concentration A+/05.2
Conformity B/11.5
Conga Line B/01.2 - 4.6
Connect-N B/03.6
Connect the Dots A/03.6
Conquest B/02.9
Conquest Campaign C/02.5
Sums A/34.0
Conservation D/04.8
Constellation Creation C/04.7
Constrained Freedom of Choice D/04.6
Contest Advancement B/04.2
Multi-Year Contest Scheduling C/04.2
Contest Struggles A/12.2
Contingency Planning A/22.1
Continuous Median B+/03.0
Association for Control Over Minds B/04.1
Cryptographer's Conundrum A/01.5
Conversation Log B/02.8
Converting Romans A/03.8
Convex Polygon Area A/31.9
Cookie Cutters A/32.3
Cookie Selection B+/04.8
Cooking Water A/12.0
Cops and Robbers D/04.8
Cornhusker A/01.7
Corrupt Judge A/04.4
Cosmic Path Optimization A/01.3
Costume Contest A/01.9
Circuit Counting C/05.2
Count Doubles A/02.0
Counting Chocolate A/04.3
Counting Clauses A/01.5
Counting Greedily Increasing Supersequences B+/35.9
Counting Stars B/02.7
Counting Triangles A/32.0
Count the Vowels A/01.3
Course Scheduling B/01.7
Cow Crane C/03.5
CPR Number A/01.4
Exploding CPU A/35.8
Cracker Barrel Game C/24.3
Cracking RSA A/22.0
Cracking the Code B+/05.8
Cranes B/14.0
Crashing Robots B/03.3
Credit Card Payment A/15.6
Cribbage On Steroids B/24.7
Cricket Deadpool C/26.0
Criss-Cross Cables B+/04.6
Crne A/22.5
Crop Triangles (Easy) B/23.0
Cross B+/04.0
Cross Country C/02.6
Crowd Control D/13.5
Cryptographic Keys A/23.8
Cu Chi Tunnels B/23.0
Cuckoo! Cuckoo! A/03.7
Cudoviste A/01.4
Stacking Cups A/01.6
Curse the Darkness A/12.5
Curveknights C/13.6
Stacking Curvy Blocks A/24.7
Cut in Line B/01.6
Cutting Brownies E/14.1
Cutting Corners A/32.8
Cutting the Necklace B+/05.7
Cyanide Rivers A/02.2
Cycles (Easy) D/23.9
Cyclical Periods B/02.6
Cypher Decypher A/01.5
Dagatal A/01.2
Daily Division E/06.1
Damaged Equation A/02.5
Dams in Distress B+/03.7
Dance Recital E/03.9
Dangerous Skiing C+/18.3
The Darkness C/07.3
Dartboard A/2+4.1
Darts A/12.2
Dart Scoring B/34.2
Das Blinkenlights A/11.7
DA-Sort B/03.4
Big Data D/25.3
Dating time A/24.4
Datum A/11.5
Dead-End Detector C+/04.0
Dead Fraction A/25.1
Death Knight Hero A/01.5
Deathstar A/11.8
Death and Taxes A/13.1
Deceptive Dice C/13.0
Decimal deletion A/01.3
Decisions, Decisions B/12.9
Deduplicating Files B/24.1
Deildadrottnun A/13.3
Deildajöfnuður B/02.3
Deild Goðsagnanna A+/13.2 - 4.0
Delft Distance C/03.9
Delimiter Soup B/01.9
Postal Delivery C/12.8
Destination Unknown D/03.9
Detailed Differences A/01.4
Detour C/04.8
DEX Save B/24.5
D Fyrir Dreki A/11.3 - 1.4
Diagonal Cut A/34.0
Dice and Ladders B+/38.1
Dice Betting C/24.2
Dice Cup A/11.4
Dice Game A/11.5
Die Hard A/13.1
A Different Problem A/12.8
Different Distances A/11.7
Digbuild B/34.4
Digi Comp II C/15.8
Digital Speedometer A/03.8
Digits A/13.1
Digit Sum A/25.8
Digit Swap A/01.2
Dihedral Group A/12.5
Ding Dong Ditch B/01.3 - 2.3
Dinner Time A/04.1
Dirty Driving B/03.5
Disastrous Doubling A/13.6
Discoveries B/05.7 - 6.3
Discrete Logging B/32.9
Disgruntled Judge A/33.6
Dishonest Lottery A/01.8
Digital display A/02.5
Distance B/13.8
Distributing Poffins A/12.1
Divide and Conquer A/37.7
Divide by 100... A/14.0
Divisible Subsequences B/33.1
Divisors A/35.3
Divisor Shuffle A/25.0
Divvying Up A/11.5
DNA A+/04.8
Dobra C/14.0
Doctor Kattis E/14.6
Dodecaphony A/23.1
Dog & Gopher A/12.4
Dominating Duos C/06.8
Dominoes 2 C/02.7
Dominos C/04.0
Don't Be Fake B/02.2
Don't Fall Down Stairs A/02.1
Don't Fence Me In C/34.5
Doorman B/02.3
Double Dealing C/37.0
Double Password A/11.6
Doubleplusgood A/02.7
Doublets D/08.2
Double Up B/04.3
Disastrous Downfall C/05.2
Disastrous Downtime C/03.0
Draft Time C/06.2
Draga Frá A/01.1
Dragon Ball I E/05.3
Dragon Balls A/15.5
Draughts C/03.6
Dreamer E/12.4
Drinking Song A/02.4
Drink Responsibly C/14.8
Driver's Dilemma A/1+2.2
Xtreme Driving E/35.4
Driving Lanes D/13.5
Driving Range C/04.0
DRM Messages A/11.6
Dropping Directions C+/03.7
Drunk Vigenère A/11.7
Daylight Saving Time A/12.1
Dual Divisibility A/24.1
Duck Pond A/03.5
Dungeon master C/03.6
Dunglish B/22.9
RA Duty Scheduler C+/03.6
DVDs A/22.8
DVD Screensaver A/37.4
Dyslectionary A/03.0
Early Winter A/01.8
The Easiest Problem Is This One A/01.6
Easter Eggs C+/15.1
Easter Holidays C+/06.2
As Easy as CAB C+/08.1
Eating Everything Efficiently C/04.6
Eating Out A/23.2
Echo Echo Echo A/01.2
Eco-driving D/27.4
Edge Removal D/06.2
Eeny Meeny B/01.9
Efficiency A/05.1
Egypt A/11.9
Eidam-Sand Lair A/04.9
Eiginnöfn B/01.3 - 2.1
Einvígi A/02.0 - 3.3
Ekki dauði opna inni A/01.4
Eko B/03.6
Elder Scrollbar A/06.9
Election B/02.4
Election Paradox A/01.8
Electrical Outlets A/01.5
Elementary Math C/14.6
Elevating the Prank A/01.6
Elevator Trouble C/02.3
Eligibility A/01.6
The Elk D/03.8 - 5.3
Ellipse Eclipse A/23.9
Elo C/01.8 - 3.3
Emergency Contest Running A/24.2
Emergency Exit C/06.0
Emag Eht Htiw Em Pleh A/01.8
Encoded Coordinates B/35.7
Encoded Message A/01.6
Endless Knight D/37.4
The End of the World B+/24.8
Endurvinnsla A/01.8
Escape from Enemy Territory C+/05.4
Engineering English B/02.6
Enlarging Hash Tables A/22.8
Entering the Time C/15.0
Enumerating Brackets C+/05.3
Envious Exponents A+/35.2
EpigDanceOff A/01.9
Equal Sums (Easy) C-/12.9
Equations A+/27.2
Equilibrium Mobile B+/13.8
Proving Equivalences D/04.8
Erase Securely A/11.6
Erdős Numbers B/04.9
Erosion Filter A/14.9
Errands D/06.0
Erratic Ants C/04.7
Escape Plan C/15.4
Escape Wall Maria C/02.8
Esej A/03.5
Esoteric Spells A+/14.0
Espresso! A/12.2
Espresso Bucks B/02.2
Integer Estate Agent A/25.1
Estimating the Area of a Circle A/11.6
Eternal Embers C/06.2
Euclidean TSP D/12.3
Euclid's Game A+/34.4
Eulerian Graphs D/02.7
Eulerian Graphs 2 B+/03.5
Eulerian Path D/04.7
Euler's Number A/22.4
European Trip A/33.6
Evacuation C+/05.6
Evening Out 1 A/12.4
Event Planning A/12.3
Even Up Solitaire B/12.4
Everything Is A Nail C+/25.4
I've Been Everywhere, Man A/01.4
Exact Change C/04.6
Exactly Electrical A/21.9
Exam A/22.2
Exam Manipulation A/04.0
Excavator Expedition C/05.1
Excellent Engineers B+/05.7
Exchange Rates C/14.9
Exchange Students B+/08.4
Kindergarten Excursion A+/03.4
Exits in Excess C+/04.1
Exoplanet Lighthouse A/12.6
Expanding Rods B/26.3
Expected Earnings A/11.8
Expeditious Cubing A/25.1
Eye of Sauron A/01.5
Factor-Full Tree E/17.3
Factorial Power A/33.0
Factors C/35.8
Factovisors A/35.6
Factstone Benchmark A/34.0
Fair Division C/13.7
Fair Play B/13.4
Fair Warning A/23.3
Fake News! A+/06.0
Faktor A/11.4
Falcon Dive A/03.1
Falling Mugs A/23.6
Falling Apart A/11.6
Falling Snow B/01.4
False Sense of Security A/01.9
Family Fares C+/03.8
Fantasy Draft B/03.8
Farey Sequence Length A/33.3
The Coloring Game 4.3 - 6.2
Färgrobot C/01.5 - 1.7
Farming Mars C+/06.0
Fast Food Prizes A/01.9
Faulty Robot C/03.7
A Favourable Ending C/03.7
FBI Universal Control Numbers A/12.2
Feistel Fun B/37.9
Fence Bowling B/22.9
Fenwick Tree E/04.0
Ferry Loading C/07.2
Ferry Loading III B/04.8
Ferry Loading IV B/02.4
Ferskasta Jarmið A/01.8 - 1.9
Fiat A/34.9
Fibonacci Cycles B/13.2
Minimal Fibonacci Sums A/12.3
Fibs og Dibs A/31.8 - 6.0
Fibonacci Tour C/15.6
Field Trip A/02.2
Framtíðar FIFA A/01.1
Fifty Shades of Pink A/01.5
Fight to Survive B/03.2
Filip A/01.4
Fimmtudagstilboð A/11.2 - 1.4
Final Exam A/01.6
Financial Planning B/14.3
Finding An A A/01.2
Find my Family B+/04.1
Find Poly C/22.9
Find the Graph C/03.5
Fire C/04.1
Firefly C/02.7
Firetrucks Are Red C/04.4
Fishmongers B/13.2
FizzBuzz A/11.5
FizzBuzz A/03.0
Fjöldi Bókstafa A/01.1 - 1.4
Flag Quiz A/13.7
Flatbökuveisla A/01.1
A Flea on a Chessboard A+/26.2
Flexible Spaces A/01.9
Fleytitala A/11.3 - 3.0
Flight Collision B/16.2
Flight Plan Evaluation B/36.8
Flip Five C/02.6
Flip Flow A/02.1
Flipping Cards E/06.5
Flipping Patties A/02.4
Floating Formation E/05.8
Flooding Fields C+/16.3
Flood-It C/03.9
Floor Plan A/23.9
Floppy Music C/05.3
Flower Garden A/23.8
No Trees But Flowers A/25.8
Flowery Trails C/03.5
Flow Layout A/01.8
Flow Shop C/02.2
Fluortanten A/11.2 - 3.2
Flygskam C/24.0
Flying Safely A/21.7
Flýtibaka A/01.4
Birthday Memorization B/01.1 - 1.6
Folded Map E/05.4
Folding a Cube C/25.3
Font D/23.9
Fountain C/02.0
Fooling Around C/25.4
Foosball Dynasty B/04.4
Forced Choice A/01.5
Forest Fires C/02.8
Forest Fruits C+/04.3
Forests B/03.3
Four Die Rolls A/02.6
Fractal Area A/22.8
Continued Fraction A/23.5
Fractional Lotion A/22.8
Framvindustika A+/11.7 - 3.4
Freckles C/03.4
Free Food A/01.5
Free Weights B+/04.0
Friday the 13th A/12.0
Fridge A/13.5
Friend of a Friend C/06.2
Frogger C/25.5
Froggie A/06.2
From A to B A/02.5
Frosh Week C/03.8
Frosh Week B/02.3
Frosting on the Cake A/23.9
Frozen Rose-Heads B/04.8
Fruit Baskets C/24.6
Frumtölutalning 1.4 - 8.5
Frustrated Queue C/04.9
Functional Fun A/12.1
Fundamental Neighbors C/23.1
Fun House B/02.1
Fuzzy Family Tree C/03.8 - 4.7
FYI A/01.3
Fyrirtækjanafn A/01.3 - 1.8
Galactic Warlords B/26.8
Game Night D/14.9
Game of Cards E/25.8
Game Rank A/03.6
Game Suggestions C/05.0
Game Theory C/03.9
Gandalf's Spell B/02.2
Gangur A/01.3 - 2.5
GCD A/11.5
GCDs D/24.8
Galactic Collegiate Programming Contest B+/05.0
GCVWR A/01.4
Gear Changing A/13.8
Gears C/13.5
Gears and Axles A/13.4
Geezer Scripts C/02.8
Genealogical Research B/03.8
Gene Block A/12.4
Chinese Remainder Theorem (non-relatively prime moduli) A/33.5
Generalized Recursive Functions C/14.5
Genetic Search B/02.2
Genius C/13.3
George D/02.0
Geppetto C/22.4
Gerrymandering A/11.6
Get Shorty C/03.4
Getting Through C+/15.8
Get to Work B/02.6
Ghostbusters 3 A/34.0
Ghost Leg A/01.5
Gig Combinatorics A/23.8
Gini Stuðull A/11.3 - 3.9
Git Good 1.5 - 3.3
Glasses Foggy, Mom's Spaghetti A/12.3
GlitchBot A/01.9
Glossary Arrangement C+/06.5
Glyph Recognition A/22.7
Goat Rope A/11.6
Goat Ropes E/16.7
Going to Seed B+/06.3
Getting Gold C/02.6
Goldbach's Conjecture A/22.1
Golf B+/01.5 - 8.7
Golomb Rulers B/03.0
Good Coalition C/13.8
Good Messages A/04.2
Good Morning! A+/02.6
Goofy Geometry A/24.8
Goomba Stacks A/01.5
Gopher II C/04.0
Gorillas A/36.9
The Gourmet C/01.8
Grade Curving A/14.8
Grading A/01.6
Graduation Guarantee C/13.7
Grand Opening D/06.2
Grandpa Bernie B/02.5
Granica A/25.5
Through the Grapevine C/03.9
Watering Grass D/14.0
Gregory the Grasshopper C/03.3
Grass Seed Inc. A/11.4
Gravity C/04.8
Grazed Grains A/12.8
GREAT + SWERC = PORTO C/04.4
Greedily Increasing Subsequence A/01.9
Greedy Polygons A/11.7
Greedy Polygons Revisited B/35.3
Green Eggs and Ham E/08.5
Greener Tuborg A/16.9
Greeting Card B/24.0
Greetings! A/01.3
Grid C/02.6
Grid Game C+/05.2
Grid Magic A+/12.6
What's on the Grille? A/13.5
Groupthink A/22.3
Growling Gears A/21.8
Guardian of Decency C/05.0
Guess the Number B/02.5
Guessing Game A/23.2
I Can Guess the Data Structure! B/02.7
Guess Who A/01.7
Guillaume A/11.7 - 3.5
Gullpeningastaflar A/12.3 - 4.0
Gwen's Gift B/35.6
Gyrating Glyphs 6.0
Háhýsi A/11.7 - 3.0
Haiku E/05.0
Watch Out For Those Hailstones! A/02.2
Hakkari 1.3 - 1.4
Half a Cookie A/11.8
Hall O' Wee Mirrors A/34.9
Hamiltooonian Hike C+/05.3
Hamming Ellipses C/12.9
Han 4.3
Hanging Out on the Terrace A/01.4
Hangman A/01.5
Happy and Unhappy Numbers C/06.7
Happy Happy Prime Prime A/22.1
Hard Drive A+/03.4
HARDFLOR A/24.0
Hardware B/12.1
Hardwood Species B/12.6
Harshad Numbers A/11.4
Haughty Cuisine A/01.7
Haunted Graveyard D+/06.0
Hay Points B/02.1
Head Guard A/02.3
Heart Rate A/11.5
Heating Up C+/06.4
Height Ordering A/01.9
Heimavinna A/01.3 - 1.5
Heir's Dilemma A/11.5
Heliocentric A/22.0
Hello World! A/01.1
Government Help A+/26.3
Help a PhD candidate out! A/01.4
Helpful Currents C/06.9
Help Me With The Game A/02.9
What Does It Mean? C/24.8
Herkabe D/26.2
Herman A/11.8
Hermits B+/03.0
Heroes of Velmar A/02.1
Hidden Password B/02.5
Hiding Places C/01.7
High-quality Tree B/06.0
Highway to Mount Fansipan B/24.1
Hills in Gothenburg C/03.3
H-Index A/03.3
Hipp Hipp A/01.1
Hipp Hipp Húrra A/01.2
It's Hip to Be Square A/01.6
Hissing Microphone A/01.3
Historic Exhibition B/04.6
Hitastig 1.4 - 1.5
Hittast C/01.5 - 2.8
Hitting the Targets A/11.6
Hlaupafmæli A/12.3 - 3.0
Hnappasetningaskipti B/01.4 - 2.1
Semi-prime H-numbers A/35.1
Höfundaleit B/01.4 - 2.3
Hogwarts C/05.1
Holey N-Queens (Batman) B+/02.6
Holiday Stars A/36.2
Honeycomb Walk C/02.9
Honey Heist C/13.5
Honi C/03.3
Hópavinna C/02.3 - 3.0
Hopscotch A/35.6
Hopscotch 50 C/02.6
Horror List C/02.8
Horror Film Night C/03.3
Höskuldarháska B/02.8
Hotels C+/26.9
Hot Hike A/01.9
Hot Spot C/06.9
Hot Springs B/02.6
House Lawn B/14.0
House of Cards A/13.5
Howl A/02.0
How Many Digits? A/24.1
How many 0's? A/23.7
Hraðgreining A/01.1 - 1.2
Hraðskrif B/02.8 - 4.6
Hringvegurinn E/02.4 - 4.7
H to O B/12.7
Huge Campus D/04.3
Human Cannonball Run C/12.1
The Amazing Human Cannonball A/11.6
Hungarian Services E/04.2
Hunt the Wumpus A/02.1
Hurricane Danger! A/33.7
Hvert Skal Mæta? A/01.5
Hyacinth C/05.3
Hydra's Heads A/21.9
Hamiltonian Hypercube A/23.4
Pascal's Hyper-Pyramids B/34.4
iBoard A/12.4
Ice Cream C+/15.9
I Could Have Won A/03.2
ICPC Awards A/01.6
ICPC Record Matching A/04.1
ICPC Team Generation C/04.7
ICPC Team Selection A/12.9
An I for an Eye A+/04.3
if-then-else E/07.6
Ignore the Garbage A/13.1
Igra B+/04.8
Iks B/23.1
Illiteracy C/03.1
Illuminati Spotti A/02.1
Image Compression B/06.8
Image Decoding A/03.3
Image Processing A/01.8
Imperfect GPS A/24.2
Implementation Irregularities A/13.2
Import Spaghetti D/05.4
#include<scoring> B/16.1
Incognito A/22.9
Increasing Subsequence D/03.7
An Industrial Spy E/22.9
Infinite 2D Array A/35.6
Infinite Slides B+/33.4
In Flagrante Delicto D/04.5
Inflation A/12.0
Inflation B/01.2 - 2.9
A Question of Ingestion C/05.5
Inheritance A/13.4
Innvolsarinnihaldslýsing B/02.5
Input Scandal A/01.5 - 1.8
Inquiry I A/02.4
Tree Insertion A/22.9
Inspecting Illumination A+/25.3
Integer Division B/23.1
Integer Lists A+/04.3
Interesting Integers A/34.6
Intergalactic Bidding A/24.0
International Dates A/01.5
Interpreter A/03.4
Interval Cover D/05.3
Interval Scheduling B/01.6
Interview Question A/03.1
Inventing Test Data C+/05.2
Inverse Factorial B/25.3
Inverted Deck B/04.5
Invoker (Easy) A/12.3
Invoker (Hard) A/22.9
IOU C/04.2
I Repeat Myself I Repeat Myself I Repeat A/02.5
Iron and Coal D+/05.0
Irrational Division C/14.1
ISBN Conversion A/15.3
Is It Even? A/12.9
IsItHalloween.com A/01.3
Island Buses C/06.7
Island Hopping C/02.4
Islands in the Data Stream B/02.9
Islands C/01.9
Is Y a Vowel? A/01.3
Item Selection A+/06.3
God Save the i-th Queen D/05.8
It's a Secret A/05.2
I Wanna Be The Very Best A/02.9
Jabuke A/31.7
Jack-O'-Lantern Juxtaposition A/11.2
Jackpot A/23.2
Jack The Lumberjack B/15.1
Tag 1.3 - 2.2
Jailbreak D+/05.2
Jamboree A/03.0
Jane Eyre B/03.7
Janitor Troubles B/31.5
Jazz it Up! A/12.1
Jet Set A/14.5
Jewelry Box A/21.8
Jigsaw A/14.1
Job Switching A/32.5
Job Expenses A/01.5
Chicken Joggers C/05.2
Join Strings B+/02.9
Joint Attack A/12.5
Joint Jog Jam A/11.7
Jolly Jumpers A/03.2
Joyless Game A/14.1
Judging Troubles B/02.6
Judging Moose A/11.5
Juggling Patterns A/15.8
Jug Hard A/23.5
Juice C/05.4
Julmust B/12.2 - 2.4
Jumbo Javelin A/01.3
Jumping Yoshi C+/06.1
Space Junk A/24.0
Jupiter Orbiter C/06.1
Jurassic Jigsaw C/02.6
Jury Jeopardy C/02.3
Just a Minute A/12.0
Just Enough Water B/04.5
Just for Sidekicks E/03.6
Just Passing Through C+/05.1
Kafkaesque A/02.1
Cookies A/01.7 - 1.8
Kaleidoscopic Palindromes A/22.7
Running Race B/02.6 - 3.1
Karl Coder B/03.9
Karte A/01.5
Throwing bridges C/02.1 - 7.4
Kastenlauf C/03.1
Kattis's Quest B/03.5
Kayaking Trip B+/04.8
kcuD dlanoD A/01.8
Keep Him Inside A/35.9
Keep it Cool B+/02.9
Kemija A/01.7
Keyboards in Concert D/03.3
Keyboardd B/02.5
Keylogger A/01.3 - 2.5
Matrix Keypad A+/03.6
Keys, Phone, Wallet A/01.3
The Key to Cryptography A/01.7
Keywords B/01.9
Kiki Boba A/01.1 - 1.3
Killing Chaos B+/05.7
Kínahvísl A/01.2 - 1.4
K-In-A-Row A+/03.9
King of the Waves C/04.8
King's Colors A/34.3
Kitchen Measurements C/03.7
Kitchen Combinatorics B/25.0
Kitten on a Tree B/01.6
Kleptography A/11.7
The Clock A/11.5 - 1.9
Klósettröð B/02.1
Knapsack C/04.0
Knapsack Packing C+/06.0
Knight Jump C/02.3
Knight Packing A+/01.3
Knight Search C/03.1
Knights in Fen C/03.6
Knigs of the Forest B/04.3
Knitpicking B/03.0
Knitting Pattern A/13.1
Knot Knowledge A/01.4
Codforces A+/01.3 - 5.4
Kolinje A+/16.3
Kolkrabbaleikarnir A/32.2 - 8.1
Kolone A/03.3
Consulting Gigs C+/05.1
Buying Books B/02.1 - 3.6
Kornislav A/11.5
Križaljka A/01.8
Kuggfrågan C/02.9 - 3.8
Kutevi A/12.5
Kveðja A/01.1
Ladder A/11.5
Ladice C+/04.0
Lægð yfir landinu B/01.3 - 1.5
Lamps A/11.4 - 3.0
Land Equality A/05.2
Landlocked D/06.4
Landscape Generator B/03.3
Laptop Sticker A/01.5
Laptop Stickers A/02.3
Largest Hoarding B+/03.6
Last Factorial Digit A/11.3
Last Minute A/12.7
Lava C/16.1
Lawn Mower A/11.9
LCM Thief A/25.9
Learning to code E/07.1
Left and Right A/02.9
Left Beehind A/01.6
Leggja saman A/01.1
Leiðangur B/01.3 - 2.1
Lektira B/02.7
Lemonade Trade C/15.7
Less vs. Fewer A/02.1
Leyniþjónusta A/01.1 - 1.3
License to Launch A/01.5
Liðaskipting 2 A/11.5 - 2.6
Liftkarta E/04.3 - 6.3
Light Up A/02.5
Limbo: Part 1 A/23.7
Limbo: Part 2 A/23.8
Linden Mayor System B/02.3
Linear Recurrences B/35.1
Lines Per Hour A/01.8
Line Them Up A/01.7
Línuhlýnun B+/12.6 - 5.7
Lipschitz Constant B/23.7
Liquid Assets A/03.1
Listen To Your Boss D/04.4
A List Game A/22.9
Litespace E/15.1
Locked Treasure A/22.4
Locust Locus A/11.8
LogDB A+/03.8
Logland B/15.4
Logo A/12.3
Lög um lög A/02.6 - 4.3
Longest path in a DAG C/03.4
Longest Prime Sum A/12.4
Longest Increasing Subsequence D/04.9
Long Swaps A/23.6
Loopy Cab Drivers D/06.3
Loopy Transit C+/23.6
Loo Rolls A/12.1
The Dragon of Loowater A/02.1
Lopsided Lineup B/22.9
Lost In The Woods A/33.6
Lost Lineup A/01.6
Lost Map C/01.9
Low Order Zeros A/34.0
ls C/04.9
Lubbi Lærir A/01.1
Lucky Numbers C/24.1
Luhn's Checksum Algorithm A/11.7
LumberCraft B+/14.7
Lyklagangriti B/01.3 - 3.9
Mæting B/01.4
Mætingarlisti A/01.5
Mafija D/06.5
The Magical 3 A/25.5
Magical Cows A+/15.1
Association of Cats and Magical Lights E/25.6
Magical Runes A/13.5
Magic Cube A+/24.9
Magic Sequence D/08.1
Magic Trick A/01.5
Magnesium Supplementation B/24.6
The Mailbox Manufacturers Problem C/02.4
Majór Skýrsla A/13.2
Majstor A/02.5
Making A Meowth A/11.8
Malfunctioning Robot A/13.8
Mali B+/05.4
Mall Mania C+/04.7
Mancala A/02.1
Mandelbrot A/12.9
Manhattan Mornings E/05.1
Manhattanstíflur C+/04.2 - 6.7
Identifying Map Tiles A/11.7
Marbles On A Tree C/03.0
March of the Penguins D/13.9
Marko A/01.8
Mars Window A/12.4
Martian DNA A+/01.2 - 4.0
m-ary Partitions C/13.4
Massive Card Game B+/03.1
Mastering Mastermind B/02.3
Match Game A/04.6
Matchsticks A/23.9
Mathemagicians A/04.8
Math Homework A/21.9
Math Trade C/03.1
Math Worksheet A/04.8
Matrix Inverse A/23.2
Maximum Number of Colinear Points B/23.8
Maximum Flow C+/04.5
Maximizing (And Minimizing) Your Winnings C/04.0
Maximizing Your Pay D/05.2
Maximum Choice 4.0
Maximum Fix B/03.8
Maximum Rent A/33.2
The Maze Makers C/03.4
Maze Movement C/13.6
Mean Words A/01.8
Imperial Measurement A/12.0
Message A/01.3 - 1.5
Meeting Points A/35.3
Mega Inversions E/12.8
Three-State Memory A/37.8
Memory Game A/06.3
Memory Match A/23.9
Menger Sponge B/14.6
Menu Updates B/04.1
Meow Factor A/23.1
Mergjað Mál A/01.4
Messages from Outer Space C/04.9
Metaprogramming B/12.1
Methodic Multiplication A/01.6
Metronome A/01.2
Mia A/12.0
Miði A/01.2 - 2.0
Milestone Counter B/13.2
Millifærsla A/01.2
Millionaire Madness D/12.2
Minimum Cut C/03.5
Minecraft Dungeons C/07.5
Minesweeper 1.4 - 1.5
Mini Battleship B+/04.6
Minimum Scalar Product A/11.7
Minor Setback B/13.6
Minesweeper Squared A+/27.3
Minimum Spanning Tree C/04.0
Mirror Images A/02.1
Mirror Strings A/24.2
Misa A/12.0
Missing Gnomes A/03.6
Missing Number A/03.8
Missing Number A+/06.4
Missing Numbers A/01.8
Mixed-Base Arithmetic A/15.7
Mixed Fractions A/11.6
Mixtape Management A/03.9
Mjehuric B/01.7
Moderate Pace A/01.5
Modified Gray Code A/13.3
Modular Arithmetic A/22.9
Modulo A/01.4
Modulo Data Structures E/25.0
Modulo Solitaire C/03.0
Molecules A+/23.6
Molekule C/03.4
Money Matters C/12.9
Traveling Monk B+/03.3
Monopoly A/11.3 - 1.4
Let's Play Monopoly! C/04.7
Monument Maker A+/04.2
Just A Few More Triangles! E/36.3
Morse Code Palindromes A/03.0
Intergalactic Mortgage A/36.0
Moscow Dream A/11.8
Mosquito Multiplication A/11.9
Most Difficult A/33.9
Mountain Biking A/23.0
Movie Collection E/04.3
Movie Night C+/26.5
Moving Day A/02.2
Mravi C/12.4
Mravojed A/06.5
MrCodeFormatGrader A/02.0
Mr. Noodle B/16.7
Muddy Hike D/03.0
Mult! A/12.1
Multigram A/02.7
(More) Multiplication A/14.3
Multiplication Game E/24.8
Multiplication A/11.3 - 2.0
Multiplication Table A/22.9 - 3.6
Mumble Rap 1.4 - 1.6
Musical Chairs B+/03.1
Musical Notation A/02.1
Musical Scales B/01.7
Musical Trees A/03.1
Music Collection B/04.3
Music Your Way B/02.2
Muzicari C+/04.8
Mylla A/01.5
Nafnagift C/01.7 - 1.8
Name Generation A/02.7
Palindrome Names A/04.1
Name That Permutation B/34.2
Namnsdag A/01.6
Námsleið C/02.3 - 3.0
Narrow Art Gallery C/03.2
Nasty Hacks A/01.3
Natjecanje C/02.0
Natrij A/12.9
Nature Reserve C/04.2
Necklace Decomposition E/04.4
Neighborhood Watch A/23.0
Nered A+/13.7
Nested Shapes A/13.2
Neutral Ground C/03.3
Wireless is the New Fiber C/23.3
Nicknames B/03.6
Nikola C/4.2
Nimionese A/02.2
I Hate The Number Nine A/22.7
Nine Knights A/02.1
Nine Packs C/13.7
Ninety-nine A/11.2 - 3.4
Nizovi B/03.1
No Duplicates A/01.4
Non-negative Partial Sums A+/06.8
Non-Prime Factors A/35.8
Noonerized Spumbers B/02.7
NOP A/02.0
Not Amused B/02.4
No Thanks! A/02.1
No Way? Many Ways! C/14.1 - 6.2
N-Puzzle A/11.7
N-sum A/01.3
Determining Nucleotide Assortments A+/03.4
Number Colosseum B/03.5
Number Fun A/21.6
Numbers A/37.8
Number Sets C/24.4
Number Sets (Hard) C/26.9
Number Squistem E/03.2
Numbers On a Tree B/12.5
Ocean Currents D/05.2
Odd A's, Even B's A/34.4
Odd and Even Zeroes B/36.1
Odd Binomial Coefficients A/33.3
Odd Echo A/01.3
Odd Gnome A/01.6
Oddities A/01.3
Odd Man Out B-/01.5
Odds of Mia A/22.4
Office Number B+/04.7
Office Space A/04.5
Off-World Records A/01.5
Öfugsnúið A/01.2 - 1.6
Oktalni A/11.8
Okvir A/02.1
Okviri A/02.2
Older Brother A/23.2
Olympus Måns A/14.6 - 5.4
On Average They're Purple C/03.0
One Chicken Per Person! A/01.6
Ones A/24.4
Open-Pit Mining D/04.2
Open Source B/03.5
First Orchard C/24.1
Ordered Problem Set A/01.9
Orderly Class A+/03.8
Restaurant Orders C/04.9
Ordinals A/01.9
Ordinary Ordinals A/24.4
Organ-free Man A/06.2
Origami A/35.9
Ornaments A/12.6
Östgötska A/02.0
Otpor E/14.0
Outing C/05.6
Out of Sorts B/02.4
Outsourcing E/08.3
OvalWatch B/02.9
Overdraft A/02.1
Overlapping Maps B/34.6
Over the Hill, Part 1 A/22.5
Over the Hill, Part 2 E/37.0
Óvissa A/01.1
The Owl and the Fox A/21.8
Ozljeda C/24.3
Pachinko Probability C/25.3
Pachyderm Peanut Packing A/12.0
Page Layout D/15.2
Paintball C/03.2
Paint Buckets B+/05.0
Paintings B/13.4
Pairing Socks B/02.7
Packagemanager A/01.6 - 1.9
Palindrome Substring C/03.9
Palindromic Password B/04.0
Pallatölur A/01.8
Panda Chess D/06.0
Parallel Analysis C/04.6
Parket A/22.3
Parking A/01.9
Parking A/01.6
Parsing Hex A/12.6
Particle Collision A/35.6
Party Game B/33.7
Pascal A/23.5
Password Hacking A/21.9
Path Crossings B/03.0
Paths D/01.3 - 4.3
Path Tracing B/03.2
Patuljci B/01.7
Paul Eigon A/11.8
Pawn Shop B/13.4
Peach Powder Polygon A/02.0
Pea Pattern A/04.3
Pearls B+/03.5 - 5.6
Pear-wise Voting C/04.1
Pea Soup and Pancakes A/02.0
Pebble Solitaire C/02.2
Pebble Solitaire C/02.3
Pedal Power C/07.3
Peg A/01.9
Peg Game for Two C+/03.2
Pencil Crayons A/01.5
Peningar A/11.2 - 2.1
Peragrams A/01.9
Perfect Path Patrol B+/15.9
Perfect Pth Powers A/25.3
Periodic Strings A/02.3
Perket A/02.1
Permutation Code A/22.3
Permutation Descent Counts A/22.0
Permutation Encryption A/12.2
Permuted Arithmetic Sequence A/12.0
Persistent Numbers A/24.2
Pervasive Heart Monitor A/01.7
Pet A/01.5
Pharmacy B+/04.4
Phone List B/03.2
Pianino B/14.4
Piano Lessons C/03.5
Pick up sticks C/04.0
Pie B/13.1
Piece It Together E/05.5
Piece of Cake! A/11.4
Pig Latin A/02.8
A Vicious Pikeman (Easy) B/12.9
Pinni Frændi A/01.4 - 2.2
Pipe Rotation C/03.5
Pitch Performance A/25.0
Pivot B/02.4
Pizza Delivery A/14.5
Pizza Crust A/11.6
Pizza Hawaii B/02.4
Pizza Party! C/06.3
Pizzubestun A/02.1
Planetaris A/02.1
Planet Hopping C/03.2
Planets B/02.9
Planina A/11.5
Planting Trees A/01.7
Platforme B/02.9
Platform Placing A+/15.0
Playfair Cipher B/02.8
Playground A+/14.9
Playing the Slots E/23.3
Please, Go First B/03.4
Plotting Polynomials A/22.5
Mr. Plow King B/33.2
Plus Minus A/35.2
Point in Polygon A/35.3
Pokechat A/01.5
Poker Hand B/01.4
Polish Notation B/03.7
The Uncertainty of Politics C/15.3
Polygon Area A/22.3
Polynomial Multiplication 1 A/21.8
Polynomial Multiplication 2 E/35.8
Pop! A/33.8
Popcorn A/11.4 - 3.1
Poplava A/34.1
Popularity Contest A/01.9
Immortal Porpoises A/32.6
Positive Divisors A/13.0
Pot A/11.3
Potion Commotion A/13.9
Powers and Modulus A/24.9
Powers of 2 (Easy) A/02.2
Power Strings C/25.4
Predicting GME C/03.3
Prefix Free Code B+/36.9
Prerequisites? A/02.0
Presidential Elections C/25.4
Pretty Good Cube Root B/14.3
Primality A/32.5 - 5.4
Primal Representation B/24.3
Primary Arithmetic A/13.0
Prime Count C/33.1 - 8.6
Prime Matrix A/34.3
Prime Path C/22.1
Prime Reduction C/22.6
Peculiar primes B/25.9
Blackboard Numbers A/23.8
Prime Sieve A/24.9
Primonimo E/25.4
Prince and Princess D/05.3
Saving Princess Peach A/02.0
Prinova A/25.0
Printing Costs A/02.2
Pripreme A/12.8
Prjónamynstur A/01.3 - 1.5
Problem Classification B/02.9
Product Divisors B/26.5
Profitable Pizzas D/06.3
Programming Team Selection E/06.0
Programming Tutors C/04.4
Progressive Scramble A/12.2
Promotions D/06.0
Proofs B/02.5
Prosjek A/25.3
Protecting the Collection A+/04.2
Provinces and Gold A/01.4
Prozor A/01.8
Prsteni A/11.6
Prva A/01.7
Pseudoprime numbers A/23.6
Ptice A/01.6
Pub Crawl A/02.2
Pub-lic Good C/03.8
Pulling Their Weight C/04.4
Purple Rain D/03.8
Púsluspil B/01.5 - 2.1
Putovanje A/03.1
Plants vs Bad Guys A/01.3 - 1.6
Pyramid Construction A/13.8
Building Pyramids A/01.4 - 1.5
Pyro Tubes A/25.1
Quality-Adjusted Life-Year A/01.3
Qanat A/32.6
Quadrant Selection A/01.2
Quadratic Dissonance A/24.0
Quadratic Residues A/35.6
Quantum Superposition C/03.1
Verify This, Your Majesty A/12.5
The Queen's Super-circular Patio B/23.3
Quick Brown Fox B/01.6
Quick Estimates A/01.6
Quickscope B/01.3 - 4.2
Quite a Problem A/02.0
R2 A/11.3
Race Day B/03.6
Racing Around the Alphabet A/11.6
Raðgreining 1 A/01.3 - 1.6
Raðir A/02.1 - 4.3
White Water Rafting A/32.8
Ragged Right A/01.9
Raid Teams B/03.7
Railroad Map C+/07.4
Railroad A/21.5
Toy Railway C+/05.9
Railway Runner 3.6
Rainbow Road Race C/13.7
Raising the Bar B/34.1
Rampant Growth A/11.9
A Rank Problem A/02.8
Rasterized Lines B/37.8
Rating Problems A/11.3
Restaurant Ratings A/34.0
Rational Arithmetic A/13.4
Rational Ratio A/24.9
A Rational Sequence A/24.7
A Rational Sequence 2 A/22.5
A Rational Sequence (Take 3) A/12.4
RATS B/25.4
Ray Chasing A/35.0
Razbibriga A/06.2
Razgovori A+/04.1
Reachable Roads C/01.8
Reactivity Series C/03.4
Real Manhattan Distance A/26.3
Rečenice B/02.7
Scaling Recipes A/11.8
Reconstructing Tape Art B+/04.3
Recount B/02.4
Rectangle Area A/01.5
The Rectangles Are Surrounding Us! A/02.6
Growing Rectangular Spiral A/13.0
Recursion + Rand = !Fun B+/16.2
Exam Redistribution B/02.3
Red Rover A/02.2
Reduced ID Numbers B/12.4
Work Reduction D/15.6
Redundant Binary Notation C+/14.2
Reduplication A/01.1
Refrigerator Transport A/11.6 - 2.4
Primary Register A/12.3
Number Plates C/03.8 - 6.7
Relatives A/23.1
Relocation A/01.5
Remainder Reminder A/35.8
ReMorse B/32.3
Repeated Substrings E/06.1
Repeating Decimal A/23.6
Repetitive Song A/03.0
Rerouting Rapids C+/05.0
Research Productivity Index C/33.3
Reservoir B+/05.1
Reseto A/32.2
Restaurant Opening A/11.8
Retribution! B/16.3
Reversed Binary Numbers A/11.4
Reverse Rot A/11.7
Reversibly Cyclic Strings A/03.2
Reversing Roads D/03.7
Revision Control B/01.4 - 2.5
Rhyming Slang B/03.3
Rhythm Flow C/05.1
Ricochet Robots C/04.3
Riddle of the Sphinx A/22.7
Ride-Hailing D/06.3
Riječi A/11.7
Rimski B/03.7
Rhyme Power B/03.7
Rings C/14.8
Rings C/04.0
Rice judge B/01.6 - 2.0
Rise and Fall A/04.6
Robotopia A/35.4
Robot Protection E/22.6
Robots E/07.5
Robots on a Grid C/05.1
Robot Turtles C+/03.2
Rock Band C+/03.9
Rock Climbing C/05.0
Rock-Paper-Scissors Tournament A/13.6
Rock, Scissors, Paper A/04.2
Röðunarrugl A/11.6 - 2.5
Roll Call B/02.6
Roman Holidays B/15.1
Roaming Romans A/11.6
Room Painting A/02.5
Rooted Subtrees E/14.0
Rot A/03.1
Rotate and Cut A/03.7
Rounded Buttons A/13.5
Round Trips D/25.7
Royal Family Tree B/04.7
RSA Mistake A/34.3
Ruglaður listi A/23.5 - 4.4
Rule N B/03.9
Run-Length Encoding, Run! A/01.8
Running MoM C/04.0
Running Steps A/22.8
Rust A/11.9 - 4.2
Sabor C/06.3
Sacred Texts A/04.1
Cracking The Safe D/02.8
Safe Houses C/02.3
Safe Passage D/03.8
Sailing Friends C/02.1
Same Digits (Easy) A/02.4
Same Digits (Hard) A/12.5
Sammaeining C/21.9 - 6.0
Songbook B/01.4 - 2.0
Sanic A/12.6
Sannvirði B/01.4 - 2.5
Santa Klas A/13.0
Yet Satisfiability Again! D/23.6
Saving Daylight A/12.2
Saving For Retirement A/11.9
Saving the Universe C/04.1
Eb Alto Saxophone Player B/02.2
Scaling Recipe A/02.0
Mountain Scenes C/23.3
School Spirit A/11.8
Score! A/03.2
Screamers in the Storm A/33.0
Hacking the Screen E/13.7
Scrolling Sign A/03.0
A Second Opinion A/11.6
Secret Chamber at Mount Rushmore B/02.6
Secret Message A/01.7
Secret Santa A/33.2
Secret Santa Cycles C+/06.6
Secure Doors B/01.6
Line Segment Distance A/34.2
Segment Monitoring B/01.9 - 4.8
Select Group B/04.1
Self-Similar Strings B+/03.2
Selling Spatulas D/07.2
Semafori A/11.9
Sentry Robots C/03.8
Dividing Sequence A/13.5
0-1 Sequences C/25.7
Sequential Manufacturing A/03.0
Server A/01.6
Set! A/22.0
SETI A/33.5
Setnja B+/24.7
The SetStack Computer B+/25.7
Settlers of Catan B/34.1
Seven Wonders A/11.5
SG Coin A+/22.7
Shandy A/01.3
Shattered Cake A/11.4
Sheldon Numbers A/34.7
Shiritori A/02.4
Shopaholic A/02.0
Shopping D/04.9
Shopping List B/02.9
Shopping List (Easy) B/01.8
Shopping Malls C/13.8
Divisibility Shortcut A/24.0
A Shortcut to What? 1.2
Shortest Composite Sum A/14.2
Single source shortest path, non-negative weights C/03.0
Single source shortest path, time table D/13.3
Single source shortest path, negative weights D/03.9
Shortlex A/23.3
Short Sell A+/03.9
Elegant Showroom C/04.4
Shuffling Along B/02.6
Sibice A/11.4
Sideways Sorting A/02.0
Digit Product A/01.6
Bridging Signals E/02.9
Sign Profile A/25.8
Silver Star Stands Alone C/02.7
Sim B/01.1 - 3.4
Simon Says A/02.2
Simone B/01.9
Simon Says A/01.4
Simple Addition A/02.6
Simple Arithmetic A/11.2 - 4.6
Simple Cron Spec B/12.1
Simple Factoring A/12.5
Simple Solitaire A/05.1
Simplicity B/02.6
Simply Sudoku B+/03.7
The Last Pizza 1.4 - 4.0
Sith A/01.5
Sjecista A/21.9
Skák 1.3
Skammstöfun A/01.3 - 1.5
Skener A/01.4
Ski Jumping B/23.4
Ski Lifts B/04.1
Skocimis A/11.6
Graduation B/01.2 - 2.3
Going to School C/01.9 - 2.0
Skotleikur A/31.5 - 2.1
Turn It Up! A/01.3 - 1.5
Sky Islands C/02.0
Slalom 2 B/25.7
Slatkisi A/11.8
Slicice C/06.6
Slide Count B/04.3
Sliding Tiles B+/04.2
Slikar C/03.2
Slom A/34.7
Slow Leak C/05.6
Sly Students A/02.3
Smallest Calculated Value A/12.8
Smallest Multiple A/23.3
Small Schedule A/23.2
Smart Phone A/02.7
SMIL A/01.3 - 1.5
Smoothie Stand A/12.4
Snake C+/07.8
Snakes and Masters A/23.2
Snapper Chain (Easy) A/22.6
Snapper Chain (Hard) A/22.2
S-Nim B/32.3
Snjóteppa B/02.4 - 4.6
Unique Snowflakes B/03.6
Social Advertising D/03.9
Social Distancing A/02.2
Social running A/02.3
Soda Slurper A/11.6
Soft Passwords A/02.3
Sok A/11.8
Peg Solitaire C/03.1
Some Sum A/12.1
Sort B/02.7
Sort of Sorting A/01.9
Sort Two Numbers A/01.3
Sóttkví A/01.4
The Sound of Silence B+/04.1
Soundex A/02.5
Soylent A/11.7
Space Mail C/13.7
Space Race A/02.2
Sparkle's Seven C/05.3
Spavanac A/11.4
Speaking of Which A/26.9
Need for Speed B/23.1
Speeding A/11.6
Speed Limit A/11.5
Speedrun B/02.2
Speedrunning C/05.2
Speedy Escape D/05.3
Sperhling A/02.3
Spelling Bee A/02.0
Spiderman's Workout C/04.3
Prime Spiral C+/03.2
Splat A/12.6
Split Decisions B/06.8
Spritt A/01.3
Square Deal A/13.9
Square Fields (Easy) B/25.6
Square Peg A/11.6
Square Peg in a Round Hole B/12.9
Squawk Virus C/33.2
Srednji A/23.7
Sretan A/23.0
Stacking Up B/15.4
Illuminated City B/01.5 - 2.1
Stafsetning A/12.7 - 3.1
Stafur A/01.5
Staggering to the Finish A/13.3
Stalínröðun D/02.3 - 6.8
Stamp Combinations C/05.5
Biased Standings B/13.4
Star Arrangements A/11.7
Star Battles I A/02.7
A Star not a Tree? E/36.6
Star Wars Movies B+/05.5
Statistics A/01.9
Statues A/02.9
Sticky Keys A/01.5
Sticky Situation A/12.5
Stigavörður E/11.8 - 4.0
Stikl E/01.7 - 5.8
Stirling's Approximation A/34.5
Daydreaming Stockbroker A/13.1
Stock Prices B/03.6
Stogovi E/07.9
Messy lists A/01.4 - 2.2
Stol E/05.7
Stopwatch A/11.5
Stórafmæli A/01.1 - 1.2
Straights A/03.2
Stream Lag A/03.0
Streets Ahead A/02.1
String Factoring C/04.8
String Matching E/03.5
Structural Differences E/07.2
Stysti skógarleiðangurinn D/02.8 - 6.8
Subaruba A/02.0 - 3.8
Subcommittees A/35.0
Subprime A/33.9
Counting Subsequences (Hard) C/03.3
Subsequences in Substrings C/05.0
The Power of Substitution B/36.3
Substring Characters B/04.0
Repeated Substrings E/05.7
Subtraction Plus Plus Plus A/14.2
Subway Tree System B+/04.8
Subway C/15.2
Subway Map E/07.5
Subway Planning C/22.2
Successful Zoom A/02.4
Succession C/03.0
Suffix Array Re-construction C/03.9
Suffix Sorting E/05.7
Sum Kind of Problem A/11.5
Summer Trip C/03.2
Sum of the Others A/02.3
Sum Squared Digits Function A/11.5
Sun and Moon A/12.0
Supercomputer E/02.7
Superyatzy A/01.4 - 1.6
Surveillance Squared A/37.3
Suspension Bridges B/14.0
Svada B+/13.9
Svemir C/05.2
Support Vector Machine A/14.0
Swapping Places C+/07.2
Swap to Sort C/03.0
Sylvester Construction B/12.3
Symmetric Order B/01.7
Synchronizing Lists B/01.6
T9 Spelling B/01.8
Tabs and spaces A/03.4
Tai's formula A/21.5
Tajna A/12.0
Takkar A/01.1 - 1.2
Takk fyrir mig A/01.2
Taktsveðjur A/01.3 - 2.3
Talnalás C/01.9 - 3.9
Aquarium Tank B/25.0
Target Practice A/36.1
Tarifa A/11.3
Tautology B/22.9
Teacher Evaluation A/22.7
Happy Telephones C/02.8
Time Travelling Temperatures A/22.2
Temperature Confusion A/12.8
Teningasafn A/33.1 - 7.1
Tenis A/03.8
Tenkici B/25.8
Teque B/04.6
Ternarian Weights B/23.7
Terrace Hill B/03.2
Terraces C/03.7
Test Drive A/02.1
Tetration B/11.6
Tetris A/01.9
Texas Summers D/14.0
Text Encryption A/03.4
Text Messaging Outrage A/03.0
Texture Analysis A/02.9
Thank God it’s Friday A/02.9
Thanos A/12.3
Thanos the Hero A/03.1
That's One Hanoi-ed Teacher B/05.0
The Backslash Problem A/02.3
The Big Mac Question C+/08.9
The Colonization of El-gă-rizm C/05.3
The Deal of the Day B/22.2
The Grand Adventure B/02.0
The King of the North C+/04.1
The Last Problem A/01.6
The Plank B/01.6
Thermostat Trouble A/23.4
Thesaurus C/04.7
I'm Thinking of a Number A/23.9
This Ain't Your Grandpa's Checkerboard A+/01.7
Thore's self-esteem A/04.1
Thoring test B/01.8
Three Dice B/04.7
Three Powers A/22.4
Game of Throwns B/02.7
Ticket Completed? C/13.4
Plane Ticket Pricing C/04.0
Tic-Tac State A/12.6
Tic Tac Toe C/14.0
Tic Tac Toe Counting B/03.5
Tide Goes In, Tide Goes Out D/14.7
Tight words C/22.8
Tight-Fit Sudoku E/04.5
Tildes C/02.6
Til hamingju A/01.1
Timebomb A/02.0
Stuck In A Time Loop A/01.3
Time Zones A/14.1
Timing B/33.8
Tired Terry A/03.3
Toast A/24.9
Töflur A/11.7 - 2.4
Toilet Seat A/02.3
Tok Tik B/11.4 - 1.6
ToLower A/02.3
Tölvuíhlutir B+/01.8 - 6.2
Tölvunarfræðingar telja A/01.1
Tom and Jerry C/37.3
Tomography C/03.5
TomTom Cruise D/07.4
Torn To Pieces C/03.3
Tower Construction A/01.6
Töskupökkun 4.8
Töskuröðun A/12.1 - 6.2
Touchdown! A/03.9
Touchscreen Keyboard B/12.1
Tour de France B/12.8
Tourists E/14.1
Tournament Matchmaking C+/07.1
A Towering Problem B/02.8
Toys A/33.8
Track Smoothing A/21.8
Tractor 5.5
Train Addiction B+/36.5
Train Boarding B/04.2
Training A/01.6
Train Passengers A+/02.7
Train Sorting E/04.8
Tram A/22.2
Transit Woes A/21.5
Translation A/01.4
Transportation Planning C/04.6
Trapizza A/12.1
Travel the Skies B/02.9
Treasure Diving D+/06.1
Treasure Hunt B/02.5
Treasure Map A/35.9
Treehouses C/02.8
Treequivalence E/07.9
Tree Shopping B+/03.9
Three in a Row A/01.4 - 1.6
Trending Topic B/04.9
Tri B/01.8
Sierpiński Circumference A/33.0
Triangle Drama A/02.7
Triangle Ornaments A/32.2
Triangle Trees C+/05.8
Triangular Collection A/25.7
Triangle Text A/05.6
Triangle Area A/01.3
Trick or Treat B/23.2
Trik A/01.4
Triangle Trilemma A/23.4
Triolingo Push A/31.4 - 6.2
The Trip, 2007 B/03.0
Triple Sevens A/01.6
Triple Texting A/01.7
Trip Odometer B/02.2
Trip Planning A/03.5
Tri Tiling C/13.0
Trojke B/23.4
Troll Hunt A/12.4
Travelling Salesperson 2D E/01.5 - 9.5
Tunnelling the Earth A/32.9
Turbo E/04.3
Turning Trominos B/35.0
Turtle Master B/13.0
ICPC Tutorial A/23.2
Two Charts Become One B/04.1
Take Two Stones A/11.2
Two-sum A/01.2
Úllen dúllen doff A/01.6
Úllen Dúllen Doff 2 A/11.4 - 2.4
Ultimate Binary Watch A/02.0
Ultra-QuickSort C/04.4
Umferð A/01.2 - 1.3
Umm Code B/13.3
Undead or Alive A/01.4
UnDetected C/03.4
(un)Fair Play D/05.9
Union-Find C/03.8
Units C/13.3
University Zoning B/02.9
Unlock Pattern A/11.7
Unlock Pattern II A/37.1
Uno Reverse A/05.6
Unread Messages B/04.2
Arrangement A/11.2 - 1.5
The Ups and Downs of Investing A+/03.8
Urban Design A/34.2
Using Digits C/04.3
UTF-8 A/02.2
The Uxuhul Voting System C/13.1
Vaccine Efficacy A/12.9
Vacuumba A/12.0
Right-of-Way A/02.1
Vanishing Parentheses C/04.9
Variable Names B/03.4
Variable Arithmetic B/02.4
Varied Amusements C/02.2 - 3.0
Vauvau A/12.0
Veci A/11.7
Veður E/02.7 - 5.9
Veður - Lokaðar heiðar A/01.3
Veður - Vindhraði A/01.6
Vefþjónatjón A/01.5
Boiling Vegetables B+/03.5
Veggja Kalli A/02.6 - 4.0
Velkomin! A/01.0
Who wins? A/01.7 - 1.8
Victory Through Synergy E/04.3
Video Speedup A/11.8
Viðsnúningur A/01.2
Virtual Friends C/03.4
Virus Replication A+/03.6
VisuAlgo Online Quiz D/03.4
VivoParc E/05.0
Voff B+/01.2 - 4.1
Volim A/11.6
Volume Amplification B+/06.3
Popular Vote B/02.0
Vudu C/14.6
Vuk D/03.8
Waif Until Dark C/02.6
A Walk Through The Forest C/05.2
Trapezoid Walkway C/23.2
Lifting Walls B/14.5
Walrus Weights C+/02.7
Walt Bellamy C+/06.9
Warehouse B/02.3
War on Weather A/33.3
Warring Scoring A/03.1
Watchdog A/12.2
Water D/04.0
Water Journal A/02.1
Watersheds C/03.2
Waterworld A/12.3
Weak Vertices A/01.5
The Weight Of Words A/12.5
Weighty Tomes D/04.3
Welcome to Code Jam (Easy) A/02.0
Welcome to Code Jam (Hard) C/03.8
WERTYU B/03.0
Wet Tiles C/04.0
WFF 'N PROOF A+/03.0
What does the fox say? B/01.9
Wheels C/23.4
Where's My Internet?? C/02.7
Where's My Waterfall? A/03.0
Where to Live? A/13.8
Which Base is it Anyway? A/22.6
Which is Greater? A/01.2
Which Warehouse? E/06.3
The White Rabbit Pocket Watch E/14.7
Who Goes There? B/04.1
Who's the Boss? C/05.0
Wimbledon A/24.7
Win Diesel D/05.6
Wizard of Odds A/12.4
Wonky Pizza B/24.5
Wood Cutting C-/02.9
Wooden Signs C+/03.1
Word Cloud A+/02.4
Word Equations B+/07.4
Words for Numbers A/02.9
WordSpin C/05.2
Workers of the World Unite! Just Not Too Close. E/04.8
Working From Home A/04.4
Workout for a Dumbbell B+/05.3
Assigning Workstations B/01.7
Worst Weather Ever E/07.0
Board Wrapping E/23.6
XOR Equation A+/24.7
Yin and Yang Stones A/11.8
Yoda A/02.1
You Be the Judge! A/15.7
You be The Judge, Again B/03.5
Yule Lads B/32.2 - 6.8
Zadaca A/13.7
Zagrade B/03.4
Zamka A/01.5
Stand on Zanzibar A/11.4
Zapis C+/15.1
Zbrka A/35.2
Zebras and Ocelots A/13.3
Zig Zag Nametag A/13.9
Zigzag A/04.7
Zipf's Law B/05.6
Zipf's Song B/24.9
Zipline A/33.7
Znanstvenik B+/03.7
Zoning C/05.2
Zoning Houses E/16.6
Un-bear-able Zoo A/01.7
Zoom A/01.5
Zyxab B/01.5 - 2.5