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/15.0
2048 A+/02.5
So you want to be a 2^n-aire? A/32.9
3D Printed Statues A/11.9
4 thought B/02.6
Eight Queens B/03.5
A1 Paper A/13.7
Aaah! A/01.5
Abandoned Animal C-/05.5
ABC B/01.7
Ab Initio D/07.6
Above Average A/11.9
Abstract Art E/35.5
Abstract Painting A/2+4.0
Absurdistan Roads II C/36.9
Absurdistan Roads III D/05.7
Access Points B+/35.7
ACM Contest Scoring A/01.5
Association for Computing Machinery A/12.6
The Calculus of Ada C/12.6
Add 'Em Up! B+/24.9
Adding Words B+/03.6
Adjoin the Networks D/15.5
Administrative Difficulties B/06.2
Ads C/05.6
Adventures in Moving -- Part IV C/04.6
AI Jeopardy B/27.4
Air Conditioned Minions D/03.6
Akcija B/01.9
Alchemy 101 A/23.7
Alehouse D/14.7
Alex and Barb A/23.3
Alice in the Digital World A+/04.0
Alien Numbers A/21.8
All about that base A/22.8
All Different Directions B/22.5
All is Well D/16.2
Alloys A/13.8
All Pairs Shortest Path D/05.5
Almost Perfect A/3-3.4
Almost Union-Find D+/06.5
Alphabet B/02.9
Alphabet Animals B/03.3
Alphabet Spam A/01.3
Amanda Lounges C/05.2
A Mazing! C/05.4
Sheba's Amoebas C-/01.7
Amsterdam Distance A/12.5
A Multiplication Game A/24.1
Anagram Counting B/22.7
Andrew the Ant B-/25.1
A New Alphabet A/01.6
Alternative Anagram B/17.1
Another Brick in the Wall A/11.9
Another Candies A/12.5
Antenna Placement D/07.9
Anthony and Cora C/25.7
Anthony and Diablo A/12.5
Ocean's Anti-11 A/22.6
Ocean's Anti-11 (Hard) E/27.4
Antiarithmetic? A/37.6
Ants A/12.4
Apaxiaaaaaaaaaaaans! A/01.4
Honour Thy (Apaxian) Parent A/01.5
A+B Problem E/38.3
Appalling Architecture A/14.1
Appeal to the Audience C/03.0
Falling Apples A+/03.1
Johnny Applesack C/13.5
A Prize No One Can Win B/02.4
Aqueduct Construction E/16.6
Arachnophobia D/04.8
Arbitrage? D/13.6
Architecture A/03.4
Arctic Network D-/04.2
A Real Challenge A/11.5
Are You Listening? B/12.4
Arithmetic A/23.6
Arithmetic Decoding B/24.0
Army Strength (Easy) A/02.2
Army Strength (Hard) A/02.1
Array of Discord A/04.8
Amalgamated Artichokes A/1+2.5
Artwork C/25.9
ASCII Addition A/01.8
ASCII Figure Rotation A+/03.2
Ask Marilyn A/24.2
Assassins C/24.6
Association of Myths A/27.0
Astro A/34.1
Astrological Sign A/01.7
Autori A/01.2
Paradox With Averages A/12.4
Paradox With Averages (Hard) A/12.4
Average Speed A/13.4
Avion A/01.3
Avogadro A+/05.5
Avoidland A/23.4
Awkward Party B/02.6
BAAS C/05.6
Babelfish B/02.3
Baby Bites A/01.6
Babylonian Numbers A/22.1
Bachet's Game C/22.7
Backpack Buddies D/16.6
Backspace B/02.4
Bacon, Eggs, and Spam B/01.8
Bag of Tiles D/26.1
Balanced Diet C/03.9
Ball Bearings B/1+3.8
Ball Colors A/36.0
Distributing Ballot Boxes B+/15.2
Balls and Needles C/03.6
Baloni C/03.7
Banana Problem B+/14.8
Bank Queue B/03.4
Barcode B/36.9
Bard B/02.5
Bar Shelf E/01.4 - 8.2
Base-2 Palindromes A/24.2
basic E/16.8
BASIC Interpreter E/06.2
Basic Programming 1 A+/04.1
Basic Programming 2 B/03.2
Basic Remains A/13.2
Basketball One-on-One A/01.7
Batmanacci B/33.3
Exploding Batteries C/03.5
Batter Up A/11.3
Battle of Hogwarts D/06.2
Battleship C/04.5
Battle Simulation A/02.6
Baza B+/06.9
Bazen A/1+2.6
Beat the Spread! A/12.3
Beautiful Primes A/24.1
Beautiful Square A/05.8
Beavergnaw A/11.5
Beehives A/12.0
Beehives D/04.3
Bee House Perimeter C/33.9
Beekeeper A/02.4
Collecting Beepers C/04.1
Bee Problem C/34.8
Bela A/01.3
Bell Ringing A/34.6
Best Before A/13.9
Best Compression Ever A/22.1
Best Rational Approximation A/35.0
Best Relay Team B/01.8
Bicikli C/06.5
Big Boxes B/03.5
The Biggest Triangle A/34.8
Big Truck C+/03.2
Bijele A/01.3
Bike Gears B/15.3
Billiard A/11.7
Bing It On B/03.7
Bio Trip D/17.4
Bird Rescue D/15.4
Birds on a Wire A/1+3.5
Birthday Party D/03.7
Birthday Boy B/14.0
Birthday Paradox A/34.0
Bishops A/22.1
Bit 4 Bit D/07.7
Bit by Bit A/22.5
Bits B/12.3
Bits Equalizer A/23.9
Black Friday B/02.2
Black Out A/23.4
Block Crusher C/14.9
Block Game A/23.2
Boat Parts B/01.4
Bobby's Bet A/32.6
Boggle B/04.4
Accounting B/04.8
Bond E/25.2
Book Circle D/05.0
Book Club C/04.3
Booking D/15.7
Booking a Room B/01.8
Bootstrapping Number B/03.9
Boss Battle A/11.7
Bottled-Up Feelings A+/32.5
Curvy Little Bottles B/33.0
Bounding Box A/34.4
Bounding Robots A/21.6
Bowser's Pipes C/07.5
Boxes D/04.1
Alternative Bracket Notation C/04.9
Bracket Sequence B+/07.6
Bread Sorting A/34.7
Breaking Bad C/03.7
Breaking Branches A/01.6
Breaking Cake C/05.2
Brexit C/03.4
Brexit Negotiations D/04.8
Bridges and Tunnels C/02.8
Brocard Point of a Triangle D/34.1
Broken Calculator A/03.1
Broken Swords A/11.6
Brownie Points I B/12.2
Bridges D/01.5 - 2.4
Binary search tree B+/06.6
Delicious Bubble Tea A/12.3
Bucket Brigade A/14.3
Build Dependencies C/04.2
Building Boundaries A/13.6
Buka A/01.8
Bumped! D/04.3
Bungee Builder A+/03.7
Bungee Jumping A/35.2
Burrows-Wheeler E/06.0
Bus A/11.5
Bus Numbers A/02.6
Bus Numbers B/12.7
Bus Ticket C/14.9
Busy Schedule A/12.2
Button Bashing C/13.3
Buzzwords E/05.0
Cakey McCakeFace B+/03.7
Calculating Dart Scores B/02.5
Calculator E/03.1
Calories From Fat A+/12.0
Camp Lunches C/14.7
Candle Box A/22.6
Candy Distribution A/35.8
Candy Division B/33.1
Canonical Coin Systems D/05.0
Cantina of Babel D/13.5
Cantor A/22.8
Canvas Painting E/03.2
Canvas Line A+/04.1
Canyon Crossing D/06.2
Cardboard Container A/22.4
Card Hands B/05.6
Card Magic C/13.7
Card Trick B/01.7
Careful Ascent A/11.9
Carousel Rides B/12.5
Solving for Carrots A/01.3
Car Trouble C/04.4
Catalan Numbers A/23.5
Catalan Square A/23.2
Catenyms D/06.6
A Feast For Cats C/03.5
Advanced Causal Measurements E/27.4
Cave Exploration D/03.6
Cave Exploration C/03.5
CD B/04.8
CDVII B/05.9
Ceiling Function B/02.2
Cent Savings D/14.9
Opening Ceremony B/13.8
Cetiri A/11.7
Cetvrta A/01.4
Chair Hopping A/35.5
Chanukah Challenge A/11.3
Character Development A/22.2
Charting Progress B/02.1
Chatter C/03.5
Cheating at War E/03.9
Cheating a Boolean Tree D/04.7
Checking Break A+/25.6
Checking For Correctness A/24.0
Checkmate in One A/04.5
Cutting Cheese B+/12.9
Cheese, If You Please E/13.0
Chemist's vows E/03.9
Chess A/22.9
Chess Competition D/05.1
Chewbacca B/23.5
Chinese Remainder A/35.3
Preludes A/01.8
Chopping Wood B/33.2
Circuit Math B/02.3
Circular DNA C/13.2
Circumsphere A/35.3
The Citrus Intern C/13.7
Class Picture B+/06.1
A Classy Problem B/04.2
Cleaning Pipes E/25.5
Climbing Stairs A/14.0
Climbing Worm A/22.3
Clinic B+/13.3
Clock Construction B/03.2
Clock Pictures E/15.5
Closest Pair (Uniform) E/26.3
Closest Sums B/12.9
Closing the Loop A/11.5
Coast Length C/03.6
Cocoa Coalition A/25.1
Coconut Splat B/01.6
Code Cleanups A/12.4
Code Names D/34.7
Coffee Date D/25.3
Coin Stacks B/03.6
Cokolada A/22.3
Cold-puter Science A/01.3
Collapse C/03.2
Collatz Conjecture A/13.9
Collatz Conjecture D/26.8
Coloring Socks B/12.3
Coloring Graphs B+/05.3
Colorland A+/03.6
Combination Lock A/22.5
Comma Sprinkler C/04.2
Radio Commercials B/01.9
Committee Assignment E/37.5
Jumbled Communication A/12.1
Communications Satellite C/23.4
Jumbled Compass A/11.9
Competitive Arcade Basketball B/02.4
Completing the Square A/21.8
Compositions C/12.3
Compound Words A/01.7
Best Compromise A/12.0
Concentration A+/04.5
Conformity B/11.8
Connect-N B/04.3
Connect the Dots A/03.8
Conquest B/03.6
Conquest Campaign C/02.1
Sums A/34.7
Conservation D/04.5
Constrained Freedom of Choice D/04.6
Multi-Year Contest Scheduling C/04.3
Continuous Median B+/03.9
Association for Control Over Minds B/04.3
Cryptographer's Conundrum A/01.4
Conversation Log B/02.8
Convex Polygon Area A/31.8
Cookie Cutters A/32.4
Cookie Selection B+/04.9
Cooking Water A/11.9
Cops and Robbers D/04.2
Costume Contest A/01.9
Counting Chocolate A/04.6
Counting Clauses A/01.6
Counting Greedily Increasing Supersequences B+/34.6
Counting Stars B/02.7
Counting Triangles A/32.2
Course Scheduling B/02.0
Cow Crane C/03.9
Exploding CPU A/34.8
Cracker Barrel Game C/23.7
Cracking RSA A/22.2
Cranes B/13.7
Crashing Robots B/04.1
Credit Card Payment A/15.7
Criss-Cross Cables B+/05.6
Crne A/22.5
Crop Triangles (Easy) B/23.1
Cross B+/04.0
Cross Country C/02.7
Crowd Control D/13.2
Cryptographic Keys A/23.9
Cu Chi Tunnels B/22.9
Cudoviste A/01.4
Stacking Cups A/01.6
Curse the Darkness A/12.4
Curveknights C/13.5
Stacking Curvy Blocks A/24.1
Cutting Corners A/32.9
Cutting the Necklace B+/06.3
Cycles (Easy) D/23.9
Daily Division E/06.1
Damaged Equation A/02.6
Dams in Distress B+/04.5
Dance Recital E/04.2
Dangerous Skiing C+/18.5
The Darkness C/05.6
Dartboard A/2+4.4
Darts A/12.5
Das Blinkenlights A/11.6
DA-Sort B/02.8
Big Data D/26.2
Dating time A/24.0
Datum A/11.4
Dead-End Detector C+/03.5
Dead Fraction A/24.9
Death Knight Hero A/01.7
Deathstar A/12.0
Death and Taxes A/12.9
Deceptive Dice C/12.9
Decisions, Decisions B/13.3
Deduplicating Files B/24.5
Delimiter Soup B/02.0
Postal Delivery C/13.1
Destination Unknown D/05.4
Detailed Differences A/01.4
Detour C/04.7
Diagonal Cut A/33.6
Dice and Ladders B+/38.1
Dice Betting C/23.5
Dice Cup A/11.3
Dice Game A/11.5
A Different Problem A/12.2
Different Distances A/11.6
Digbuild B/34.1
Digi Comp II C/15.8
Digits A/13.7
Digit Sum A/25.4
Dirty Driving B/02.1
Disastrous Doubling A/13.6
Discrete Logging B/35.3
Disgruntled Judge A/34.1
Digital display A/02.3
Distance B/15.5
Divide and Conquer A/37.4
Divide by 100... A/14.3
Divisible Subsequences B/34.2
Divisors A/35.0
DNA A+/04.7
Dobra C/13.0
Doctor Kattis E/14.1
Dodecaphony A/22.7
Dog & Gopher A/12.5
Dominoes 2 C/03.3
Dominos C/06.5
Don't Fence Me In C/35.1
Doorman B/02.3
Double Dealing C/36.8
Doubleplusgood A/02.6
Doublets D/08.4
Disastrous Downfall C/03.7
Disastrous Downtime C/03.3
Draft Time C/06.4
Dragon Ball I E/04.3
Dreamer E/12.1
Drinking Song A/02.3
Drink Responsibly C/14.1
Driver's Dilemma A/1+2.0
Xtreme Driving E/35.2
Driving Lanes D/13.5
Driving Range C/03.6
DRM Messages A/11.4
Dropping Directions C+/04.0
Drunk Vigenère A/11.5
Daylight Saving Time A/12.1
Dungeon master C/03.9
Dunglish B/22.5
RA Duty Scheduler C+/04.3
DVDs A/22.8
DVD Screensaver A/38.6
Dyslectionary A/03.0
Early Winter A/01.8
The Easiest Problem Is This One A/01.5
Easter Eggs C+/15.2
As Easy as CAB C+/09.1
Eating Everything Efficiently C/03.2
Eating Out A/23.0
Eco-driving D/25.9
Edge Removal D/06.3
Eeny Meeny B/01.8
Egypt A/11.8
Eko B/04.4
Elder Scrollbar A/06.8
Election B/02.3
Electrical Outlets A/01.3
Elementary Math C/15.1
Elevator Trouble C/02.9
Eligibility A/01.5
Emergency Contest Running A/23.4
Emag Eht Htiw Em Pleh A/01.6
Encoded Coordinates B/35.8
Encoded Message A/01.4
Endless Knight D/37.5
The End of the World B+/24.6
Escape from Enemy Territory C+/04.6
Engineering English B/02.0
Enlarging Hash Tables A/23.3
Entering the Time C/15.1
Enumerating Brackets C+/07.0
Envious Exponents A+/34.6
EpigDanceOff A/01.8
Equal Sums (Easy) C-/12.3
Equations A+/25.4
Equilibrium Mobile B+/13.8
Proving Equivalences D/05.3
Erase Securely A/11.8
Erdős Numbers B/04.6
Erratic Ants C/04.8
Escape Plan C/15.5
Escape Wall Maria C/02.9
Esej A/03.3
Espresso Bucks B/02.2
Estimating the Area of a Circle A/11.5
Euclidean TSP D/12.2
Euclid's Game A+/34.5
Eulerian Path D/05.9
Euler's Number A/22.4
European Trip A/33.2
Event Planning A/11.9
Even Up Solitaire B/12.7
I've Been Everywhere, Man A/01.4
Exact Change C/05.0
Exactly Electrical A/22.1
Exam A/21.8
Excavator Expedition C/04.9
Excellent Engineers B+/06.2
Exchange Rates C/15.6
Kindergarten Excursion A+/03.7
Exits in Excess C+/07.0
Expanding Rods B/26.5
Expeditious Cubing A/24.6
Factors C/35.5
Factovisors A/36.3
Factstone Benchmark A/34.3
Fair Division C/13.5
Fair Warning A/24.9
Fake News! A+/05.0
Faktor A/11.3
Falcon Dive A/02.8
Falling Mugs A/24.0
Falling Apart A/11.6
False Sense of Security A/01.7
Fantasy Draft B/04.0
Farey Sequence Length A/33.6
Farming Mars C+/06.1
Fast Food Prizes A/02.2
Faulty Robot C/04.2
A Favourable Ending C/04.3
FBI Universal Control Numbers A/12.1
Feistel Fun B/37.8
Fence Bowling B/22.9
Fenwick Tree E/04.2
Ferry Loading III B/03.8
Ferry Loading IV B/03.1
Fiat A/35.9
Fibonacci Cycles B/12.8
Fibonacci Tour C/15.5
Field Trip A/02.4
Fifty Shades of Pink A/01.5
Filip A/01.2
Financial Planning B/13.4
Find my Family B+/07.0
Find Poly C/23.2
Find the Graph C/03.8
Fire C/04.2
Firefly C/03.5
Firetrucks Are Red C/04.0
Fishmongers B/13.8
FizzBuzz A/11.3
Flag Quiz A/14.0
A Flea on a Chessboard A+/25.3
Flexible Spaces A/01.8
Flight Plan Evaluation B/34.6
Flip Five C/03.0
Flipping Cards E/06.9
Flipping Patties A/02.2
Floating Formation E/05.6
Flooding Fields C+/17.7
Flood-It C/03.0
Floor Plan A/26.1
Flower Garden A/24.1
No Trees But Flowers A/26.4
Flowery Trails C/03.7
Flow Layout A/01.9
Flow Shop C/02.4
Fluortanten A/11.3 - 3.2
Flygskam C/23.8
Flying Safely A/21.7
Birthday Memorization B/01.3 - 1.8
Folded Map E/05.0
Folding a Cube C/25.2
Font D/24.1
Fountain C/02.2
Fooling Around C/25.7
Foosball Dynasty B/03.9
Forced Choice A/01.4
Forest Fires C/04.9
Forest Fruits C+/04.4
Forests B/03.2
Fractal Area A/23.1
Continued Fraction A/23.9
Fractional Lotion A/22.7
Freckles C/04.6
Free Food A/01.5
Free Weights B+/04.4
Friday the 13th A/11.8
Fridge A/13.1
Frogger C/24.9
Froggie A/05.8
From A to B A/02.7
Frosh Week C/05.1
Frosh Week B/02.2
Frosting on the Cake A/23.8
Frozen Rose-Heads B/06.1
Fruit Baskets C/23.5
Frustrated Queue C/03.7
Functional Fun A/11.9
Fundamental Neighbors C/24.6
Fun House B/01.9
FYI A/01.5
Galactic Warlords B/26.6
Game Night D/15.4
Game of Cards E/25.9
Game Rank A/03.2
Game Suggestions C/08.2
GCDs D/24.9
Galactic Collegiate Programming Contest B+/04.2
Gear Changing A/13.3
Gears C/13.5
Genealogical Research B/03.7
Chinese Remainder Theorem (non-relatively prime moduli) A/33.7
Generalized Recursive Functions C/14.1
Genetic Search B/02.1
Genius C/12.4
George D/02.1
Geppetto C/23.0
Gerrymandering A/11.5
Get Shorty C/03.3
Getting Through C+/15.8
Get to Work B/02.3
GlitchBot A/01.9
Glyph Recognition A/22.7
Goat Rope A/11.5
Goat Ropes E/17.4
Going to Seed B+/04.3
Getting Gold C/02.0
Goldbach's Conjecture A/22.7
Golomb Rulers B/03.0
Good Coalition C/13.7
Good Messages A/04.7
Good Morning! A+/02.6
Goofy Geometry A/24.4
Gopher II C/04.7
Gorillas A/34.5
Grade Curving A/14.5
Grand Opening D/05.7
Grandpa Bernie B/02.7
Granica A/26.3
Through the Grapevine C/03.9
Watering Grass D/15.2
Gregory the Grasshopper C/04.0
Grass Seed Inc. A/11.3
Gravity C/04.8
GREAT + SWERC = PORTO C/04.0
Greedily Increasing Subsequence A/02.1
Greedy Polygons A/11.5
Green Eggs and Ham E/08.1
Greeting Card B/24.4
Greetings! A/01.2
Grid C/03.1
Grid Game C+/04.9
Grid Magic A+/12.5
What's on the Grille? A/13.7
Growling Gears A/22.1
Guardian of Decency C/05.6
Guess the Number B/02.9
Guessing Game A/22.9
I Can Guess the Data Structure! B/02.9
Gwen's Gift B/35.5
Haiku E/04.8
Watch Out For Those Hailstones! A/02.8
Half a Cookie A/11.7
Hall O' Wee Mirrors A/34.4
Hamming Ellipses C/13.2
Hanging Out on the Terrace A/01.4
Hangman A/01.5
Happy Happy Prime Prime A/22.6
Hard Drive A+/03.2
Hardware B/12.0
Hardwood Species B/12.6
Harshad Numbers A/11.3
Haunted Graveyard D+/08.1
Hay Points B/02.0
Heart Rate A/11.3
Height Ordering A/02.1
Homework A/01.1 - 1.4
Heir's Dilemma A/11.6
Heliocentric A/21.7
Hello World! A/01.2
Government Help A+/26.9
Help a PhD candidate out! A/01.4
Helpful Currents C/05.2
Help Me With The Game A/02.4
What Does It Mean? C/25.3
Herkabe D/25.7
Herman A/11.6
Hidden Password B/02.1
Hiding Places C/01.8
Highway to Mount Fansipan B/23.4
H-Index A/03.3
Hissing Microphone A/01.3
Historic Exhibition B/05.0
Hitting the Targets A/11.7
Semi-prime H-numbers A/35.3
Hogwarts C/04.6
Holey N-Queens (Batman) B+/02.4
Holiday Stars A/35.4
Honeycomb Walk C/02.6
Honey Heist C/13.7
Honi C/03.7
Hopscotch A/35.8
Hopscotch 50 C/02.9
Horror List C/02.9
Horror Film Night C/03.3
Hotels C+/27.1
Hot Hike A/01.9
Hot Spot C/03.9
House Lawn B/13.3
House of Cards A/13.4
Howl A/01.8
How Many Digits? A/23.7
How many 0's? A/24.3
H to O B/12.4
Huge Campus D/04.3
Human Cannonball Run C/12.2
The Amazing Human Cannonball A/11.4
Hurricane Danger! A/35.3
Hydra's Heads A/21.6
Hamiltonian Hypercube A/23.1
Pascal's Hyper-Pyramids B/34.6
iBoard A/12.2
Ice Cream C+/16.4
ICPC Awards A/01.4
ICPC Team Selection A/12.8
An I for an Eye A+/04.5
if-then-else E/07.1
Ignore the Garbage A/13.1
Igra B+/04.9
Iks B/22.8
Illiteracy C/03.0
Image Compression B/04.2
Image Decoding A/03.2
Image Processing A/02.1
Imperfect GPS A/23.8
Import Spaghetti D/05.1
#include<scoring> B/13.8
Incognito A/22.8
Increasing Subsequence D/04.1
An Industrial Spy E/22.9
Infinite 2D Array A/35.0
Infinite Slides B+/33.2
In Flagrante Delicto D/04.8
Inflation A/11.7
A Question of Ingestion C/05.4
Inquiry I A/02.1
Tree Insertion A/22.1
Inspecting Illumination A+/24.7
Integer Division B/23.1
Integer Lists A+/04.3
Interesting Integers A/34.5
Intergalactic Bidding A/23.5
Interpreter A/03.7
Interval Cover D/05.9
Inverse Factorial B/25.4
Inverted Deck B/03.6
I Repeat Myself I Repeat Myself I Repeat A/02.4
Iron and Coal D+/05.0
IsItHalloween.com A/01.3
Island Buses C/07.0
Island Hopping C/02.8
Islands in the Data Stream B/02.6
Islands C/01.8
God Save the i-th Queen D/06.8
It's a Secret A/04.5
I Wanna Be The Very Best A/02.6
Jabuke A/31.8
Jack-O'-Lantern Juxtaposition A/11.3
Jackpot A/23.3
Jailbreak D+/04.8
Jane Eyre B/04.5
Janitor Troubles B/31.4
Jazz it Up! A/12.1
Jewelry Box A/21.6
Job Expenses A/01.4
Chicken Joggers C/04.7
Join Strings B+/03.9
Joint Attack A/12.7
Jolly Jumpers A/03.1
Joyless Game A/13.9
Judging Troubles B/02.6
Judging Moose A/11.4
Jug Hard A/23.7
Jumbo Javelin A/02.0
Jumping Yoshi C+/06.6
Space Junk A/24.8
Jupiter Orbiter C/06.1
Jurassic Jigsaw C/02.4
Jury Jeopardy C/02.3
Just a Minute A/11.6
Just Enough Water B/04.5
Just for Sidekicks E/03.9
Just Passing Through C+/04.8
Kafkaesque A/01.9
Kaleidoscopic Palindromes A/23.1
Karte A/01.6
Kastenlauf C/04.2
Kattis's Quest B/02.8
Keep Him Inside A/34.3
Keep it Cool B+/02.8
Kemija A/01.5
Keyboards in Concert D/03.3
Matrix Keypad A+/03.2
The Key to Cryptography A/01.7
Keywords B/02.4
Killing Chaos B+/05.4
K-In-A-Row A+/04.4
King of the Waves C/04.6
King's Colors A/34.3
Kitchen Measurements C/03.6
Kitchen Combinatorics B/25.0
Kitten on a Tree B/01.7
Kleptography A/11.5
Knapsack C/04.3
Knapsack Packing C+/07.5
Knight Jump C/02.4
Knight Search C/03.5
Knights in Fen C/03.4
Knigs of the Forest B/03.9
Codforces A+/01.4 - 5.1
Kolinje A+/15.6
Kolone A/02.6
Kornislav A/11.4
Križaljka A/01.7
Kutevi A/12.7
Ladder A/11.3
Ladice C+/02.3
Landlocked D/05.5
Last Factorial Digit A/11.3
Lava C/15.4
Lawn Mower A/12.1
Learning to code E/08.0
Left and Right A/03.4
Left Beehind A/01.5
Lektira B/03.0
License to Launch A/01.4
Limbo: Part 1 A/24.2
Limbo: Part 2 A/23.9
Linden Mayor System B/02.4
Linear Recurrences B/34.4
Line Them Up A/01.5
Lipschitz Constant B/24.6
A List Game A/22.5
Litespace E/14.8
Locked Treasure A/22.7
Logo A/12.9
Longest Increasing Subsequence D/05.6
Long Swaps A/23.2
Loopy Cab Drivers D/04.5
Loopy Transit C+/23.3
Loo Rolls A/11.7
The Dragon of Loowater A/03.0
Lost In The Woods A/33.3
Lost Lineup A/01.6
Lost Map C/02.2
Low Order Zeros A/33.9
ls C/05.5
Lucky Numbers C/24.6
Luhn's Checksum Algorithm A/11.6
LumberCraft B+/15.0
Keystrokes B/01.5 - 2.4
Mafija D/03.8
The Magical 3 A/25.8
Magical Cows A+/14.2
Association of Cats and Magical Lights E/25.5
Magic Sequence D/06.9
The Mailbox Manufacturers Problem C/02.1
Majstor A/02.1
Malfunctioning Robot A/12.4
Mali B+/05.2
Mall Mania C+/05.2
Mancala A/01.8
Mandelbrot A/12.9
Manhattan Mornings E/04.8
Identifying Map Tiles A/11.5
Marbles On A Tree C/03.0
March of the Penguins D/14.0
Marko A/01.8
Mars Window A/11.9
Mars-DNA A+/01.3 - 2.5
m-ary Partitions C/13.6
Mastering Mastermind B/02.3
Match Game A/04.8
Matchsticks A/24.3
Mathemagicians A/04.9
Math Homework A/22.0
Math Worksheet A/05.4
Matrix Inverse A/22.8
Maximum Number of Colinear Points B/25.2
Maximum Flow C+/05.6
Maximum Rent A/32.9
The Maze Makers C/03.0
Maze Movement C/14.1
Imperial Measurement A/12.0
Mega Inversions E/14.4
Three-State Memory A/37.0
Memory Match A/23.8
Meow Factor A/23.4
Messages from Outer Space C/05.1
Metaprogramming B/12.1
Methodic Multiplication A/01.6
Mia A/12.0
Milestone Counter B/12.9
Millionaire Madness D/12.7
Minimum Cut C/03.9
Minecraft Dungeons C/04.8
Mini Battleship B+/03.6
Minimum Scalar Product A/12.1
Minor Setback B/13.7
Minesweeper Squared A+/26.9
Minimum Spanning Tree C/04.1
Mirror Images A/01.6
Misa A/12.1
Missing Gnomes A/02.9
Missing Numbers A/01.5
Mixed Fractions A/11.6
Mjehuric B/01.5
Modular Arithmetic A/23.2
Modulo A/01.4
Modulo Data Structures E/24.7
Molecules A+/23.6
Molekule C/03.4
Money Matters C/13.0
Traveling Monk B+/03.4
Let's Play Monopoly! C/03.3
Monument Maker A+/04.7
Just A Few More Triangles! E/38.1
Intergalactic Mortgage A/37.4
Moscow Dream A/11.8
Mosquito Multiplication A/11.8
Mountain Biking A/22.7
Movie Collection E/04.7
Moving Day A/02.6
Mravi C/12.6
Mravojed A/06.6
Muddy Hike D/04.0
Multigram A/02.8
(More) Multiplication A/12.1
Multiplication Game E/25.0
Musical Chairs B+/03.7
Musical Notation A/01.9
Musical Scales B/01.6
Musical Trees A/03.1
Music Collection B/04.3
Music Your Way B/02.2
Muzicari C+/05.1
Palindrome Names A/03.5
Name That Permutation B/34.8
Narrow Art Gallery C/03.1
Nasty Hacks A/01.2
Natjecanje C/02.4
Natrij A/12.3
Necklace Decomposition E/04.1
Neighborhood Watch A/23.3
Nered A+/13.2
Neutral Ground C/03.3
Wireless is the New Fiber C/23.2
Nikola C/3.3
Nimionese A/02.1
I Hate The Number Nine A/23.5
Nine Knights A/01.9
Nine Packs C/14.6
Ninety-nine A/11.2 - 2.7
Nizovi B/03.4
No Duplicates A/01.4
Non-negative Partial Sums A+/04.1
Non-Prime Factors A/35.9
NOP A/02.1
Not Amused B/02.2
N-Puzzle A/12.0
Number Fun A/21.3
Numbers A/37.1
Number Sets C/24.4
Number Sets (Hard) C/26.6
Numbers On a Tree B/12.0
Ocean Currents D/05.0
Odd and Even Zeroes B/35.7
Odd Binomial Coefficients A/33.5
Odd Gnome A/01.6
Oddities A/01.3
Odd Man Out B-/01.4
Odds of Mia A/22.3
Reverse A/01.2 - 1.4
Oktalni A/11.9
Okvir A/01.9
Okviri A/01.9
Older Brother A/23.4
One Chicken Per Person! A/01.7
Ones A/24.3
Open-Pit Mining D/04.0
Open Source B/03.3
First Orchard C/23.1
Orderly Class A+/03.9
Restaurant Orders C/05.2
Origami A/34.6
Ornaments A/12.2
Östgötska A/01.6
Otpor E/14.6
Out of Sorts B/02.9
Outsourcing E/07.9
OvalWatch B/03.2
Overlapping Maps B/35.1
The Owl and the Fox A/21.7
Ozljeda C/25.2
Pachinko Probability C/25.8
Pachyderm Peanut Packing A/11.9
Page Layout D/15.8
Paintball C/04.3
Paintings B/13.4
Pairing Socks B/02.4
Palindrome Substring C/04.3
Palindromic Password B/03.7
Panda Chess D/05.9
Parallel Analysis C/03.7
Parket A/22.4
Parking A/01.8
Parking A/01.4
Parsing Hex A/12.8
Particle Collision A/34.6
Pascal A/23.7
Password Hacking A/22.1
Paths D/01.3 - 3.3
Path Tracing B/03.1
Patuljci B/01.6
Paul Eigon A/11.6
Pear-wise Voting C/04.0
Pea Soup and Pancakes A/02.4
Pebble Solitaire C/02.4
Pebble Solitaire C/03.6
Peg A/01.9
Peg Game for Two C+/03.1
Peragrams A/01.6
Perfect Path Patrol B+/15.6
Perfect Pth Powers A/25.5
Periodic Strings A/02.4
Perket A/02.3
Permutation Code A/22.3
Permutation Descent Counts A/21.9
Permutation Encryption A/12.5
Permuted Arithmetic Sequence A/12.0
Persistent Numbers A/23.9
Pervasive Heart Monitor A/01.8
Pet A/01.3
Pharmacy B+/06.2
Phone List B/04.2
Pianino B/15.6
Piano Lessons C/04.5
Pick up sticks C/03.9
Pie B/14.8
Piece It Together E/06.5
Piece of Cake! A/11.4
Pig Latin A/02.0
A Vicious Pikeman (Easy) B/13.1
Pipe Rotation C/02.7
Pitch Performance A/25.9
Pivot B/03.1
Pizza Delivery A/14.6
Pizza Crust A/11.6
Pizza Hawaii B/02.4
Planetaris A/02.4
Planina A/11.3
Planting Trees A/11.8
Platforme B/02.7
Playfair Cipher B/02.6
Playground A+/14.4
Playing the Slots E/23.0
Plotting Polynomials A/22.4
Mr. Plow King B/32.7
Plus Minus A/35.6
Point in Polygon A/35.6
Poker Hand B/01.4
Polish Notation B/03.4
The Uncertainty of Politics C/15.1
Polygon Area A/22.8
Polynomial Multiplication 1 A/21.9
Polynomial Multiplication 2 E/36.5
Pop! A/33.8
Poplava A/33.5
Immortal Porpoises A/32.8
Pot A/11.3
Powers and Modulus A/25.1
Powers of 2 (Easy) A/02.9
Power Strings C/25.6
Prefix Free Code B+/36.8
Prerequisites? A/01.9
Presidential Elections C/25.2
Primal Representation B/25.1
Primary Arithmetic A/12.6
Prime Matrix A/34.2
Prime Path C/22.3
Prime Reduction C/23.5
Peculiar primes B/25.9
Blackboard Numbers A/24.4
Prime Sieve A/25.2
Primonimo E/26.9
Prince and Princess D/06.7
Saving Princess Peach A/02.1
Prinova A/24.6
Printing Costs A/02.0
Pripreme A/12.7
Problem Classification B/03.1
Profitable Pizzas D/05.5
Programming Team Selection E/07.5
Programming Tutors C/04.2
Progressive Scramble A/11.9
Promotions D/05.7
Proofs B/02.3
Prosjek A/26.3
Protecting the Collection A+/05.4
Provinces and Gold A/01.4
Prozor A/01.6
Prsteni A/11.6
Prva A/01.7
Pseudoprime numbers A/23.2
Ptice A/01.5
Pub-lic Good C/03.5
Pulling Their Weight C/04.6
Putovanje A/02.6
Pyramid Construction A/12.4
Pyro Tubes A/25.2
Quality-Adjusted Life-Year A/01.2
Qanat A/32.2
Quadrant Selection A/01.2
Quadratic Residues A/34.9
Verify This, Your Majesty A/12.9
The Queen's Super-circular Patio B/22.6
Quick Brown Fox B/01.5
Quick Estimates A/01.3
Quite a Problem A/02.1
R2 A/11.3
Race Day B/04.1
Racing Around the Alphabet A/11.5
White Water Rafting A/33.2
Ragged Right A/01.9
Raid Teams B/03.3
Railroad Map C+/07.2
Railroad A/21.4
Toy Railway C+/06.2
Rainbow Road Race C/13.1
Restaurant Ratings A/33.7
Rational Arithmetic A/13.3
Rational Ratio A/25.5
A Rational Sequence A/25.2
A Rational Sequence 2 A/21.5
A Rational Sequence (Take 3) A/11.7
RATS B/26.2
Razgovori A+/05.9
Reachable Roads C/02.2
Reactivity Series C/03.8
Rečenice B/02.9
Scaling Recipes A/11.8
Recount B/02.2
The Rectangles Are Surrounding Us! A/03.6
Growing Rectangular Spiral A/13.0
Exam Redistribution B/02.0
Red Rover A/01.9
Reduced ID Numbers B/12.9
Work Reduction D/15.3
Primary Register A/12.0
Relatives A/23.7
Relocation A/01.5
Remainder Reminder A/35.2
ReMorse B/33.8
Repeated Substrings E/05.9
Repeating Decimal A/23.4
Research Productivity Index C/33.2
Reservoir B+/04.9
Reseto A/32.5
Working at the Restaurant B/04.7
Retribution! B/16.1
Reversed Binary Numbers A/11.4
Reverse Rot A/11.7
Reversing Roads D/04.6
Rhyming Slang B/02.7
Ricochet Robots C/03.8
Riječi A/11.6
Rimski B/04.3
Rhyme Power B/05.2
Rings C/15.1
Rings C/03.7
Robotopia A/35.6
Robot Protection E/22.6
Robots E/06.3
Robots on a Grid C/04.2
Robot Turtles C+/04.2
Rock Band C+/03.9
Rock Climbing C/05.4
Rock-Paper-Scissors Tournament A/13.9
Rock, Scissors, Paper A/04.6
Roll Call B/02.2
Roman Holidays B/14.4
Roaming Romans A/11.4
Room Painting A/03.4
Rooted Subtrees E/13.9
Rot A/03.1
Rotate and Cut A/03.1
Rounded Buttons A/12.7
Round Trips D/26.5
Run-Length Encoding, Run! A/01.8
Running MoM C/04.5
Running Steps A/22.7
Sabor C/04.5
Cracking The Safe D/02.9
Safe Houses C/02.9
Safe Passage D/04.6
Sanic A/12.2
Santa Klas A/12.5
Yet Satisfiability Again! D/23.9
Saving Daylight A/12.0
Saving For Retirement A/11.7
Saving the Universe C/04.7
Eb Alto Saxophone Player B/02.3
Mountain Scenes C/23.4
School Spirit A/11.5
Score! A/03.5
Hacking the Screen E/14.9
Scrolling Sign A/03.1
Secret Chamber at Mount Rushmore B/02.4
Secret Message A/01.8
Secret Santa A/32.7
Secret Santa Cycles C+/06.1
Secure Doors B/01.8
Line Segment Distance A/34.2
Select Group B/03.7
Self-Similar Strings B+/03.3
Selling Spatulas D/08.0
Semafori A/11.8
Dividing Sequence A/13.7
0-1 Sequences C/25.5
Sequential Manufacturing A/03.1
Server A/01.8
Set! A/21.8
SETI A/32.6
Setnja B+/25.2
The SetStack Computer B+/25.8
Settlers of Catan B/34.2
Seven Wonders A/11.4
SG Coin A+/22.4
Shattered Cake A/11.4
Sheldon Numbers A/35.2
Shiritori A/02.6
Shopaholic A/02.2
Shopping D/05.1
Shopping List B/04.5
Shopping Malls C/13.7
Divisibility Shortcut A/23.8
Single source shortest path, non-negative weights C/03.5
Single source shortest path, time table D/13.5
Single source shortest path, negative weights D/04.8
Short Sell A+/04.1
Elegant Showroom C/04.0
Shuffling Along B/02.7
Sibice A/11.4
Sideways Sorting A/02.1
Digit Product A/01.6
Bridging Signals E/05.3
Sign Profile A/24.0
Sim B/03.6
Simon Says A/02.2
Simon Says A/01.4
Simple Addition A/01.9
Simple Arithmetic A/11.3 - 4.6
Simplicity B/02.8
Sjecista A/21.7
Skener A/01.5
Ski Jumping B/23.6
Ski Lifts B/04.5
Skocimis A/11.5
Graduation B/01.3 - 1.9
Slalom 2 B/25.9
Slatkisi A/12.2
Slicice C/07.1
Slikar C/03.5
Slom A/34.7
Slow Leak C/05.8
Smallest Multiple A/23.5
Small Schedule A/23.2
Smart Phone A/02.6
Snapper Chain (Easy) A/22.6
Snapper Chain (Hard) A/22.2
Unique Snowflakes B/04.3
Social Advertising D/05.0
Social running A/02.0
Soda Slurper A/11.5
Soft Passwords A/02.3
Sok A/11.7
Peg Solitaire C/03.5
Some Sum A/11.8
Sort B/02.4
Sort of Sorting A/01.8
The Sound of Silence B+/05.2
Soundex A/02.7
Soylent A/11.5
Sparkle's Seven C/05.1
Spavanac A/11.4
Speaking of Which A/26.2
Need for Speed B/23.2
Speeding A/11.6
Speed Limit A/11.5
Spelling Bee A/01.7
Spiderman's Workout C/04.9
Prime Spiral C+/03.4
Splat A/12.2
Square Deal A/14.1
Square Fields (Easy) B/24.4
Square Peg in a Round Hole B/12.7
Squawk Virus C/33.8
Srednji A/24.3
Sretan A/23.4
Biased Standings B/13.8
Star Arrangements A/11.5
Star Wars Movies B+/06.8
Statistics A/01.7
Sticky Situation A/12.6
Stirling's Approximation A/34.7
Daydreaming Stockbroker A/13.2
Stock Prices B/03.9
Stogovi E/08.6
Stol E/06.9
Stopwatch A/11.3
String Factoring C/05.0
String Matching E/04.7
Counting Subsequences (Hard) C/03.8
Subsequences in Substrings C/05.0
The Power of Substitution B/36.1
Repeated Substrings E/06.4
Subway Tree System B+/04.7
Subway C/14.9
Subway Map E/08.8
Subway Planning C/32.1
Succession C/03.2
Suffix Array Re-construction C/04.5
Suffix Sorting E/05.9
Sum Kind of Problem A/11.5
Summer Trip C/02.7
Sum of the Others A/02.1
Sum Squared Digits Function A/11.5
Supercomputer E/03.5
Suspension Bridges B/13.5
Svada B+/13.7
Support Vector Machine A/14.8
Swap to Sort C/04.0
Sylvester Construction B/12.2
Symmetric Order B/01.6
Synchronizing Lists B/01.5
T9 Spelling B/01.6
Tai's formula A/21.5
Tajna A/12.2
Aquarium Tank B/26.0
Target Practice A/36.7
Tarifa A/11.3
Tautology B/23.4
Teacher Evaluation A/22.9
Happy Telephones C/03.2
Time Travelling Temperatures A/22.1
Temperature Confusion A/12.0
Tenis A/04.0
Tenkici B/24.7
Teque B/03.2
Ternarian Weights B/23.8
Terraces C/03.6
Tetration B/11.5
Tetris A/01.8
Texas Summers D/13.7
Text Encryption A/03.1
Text Messaging Outrage A/02.9
Texture Analysis A/02.6
Thank God it’s Friday A/03.1
Thanos A/12.9
Thanos the Hero A/03.9
That's One Hanoi-ed Teacher B/04.8
The Backslash Problem A/02.2
The Big Mac Question C+/06.8
The Colonization of El-gă-rizm C/05.4
The Deal of the Day B/22.1
The Grand Adventure B/02.1
The King of the North C+/05.1
The Last Problem A/01.6
Thermostat Trouble A/24.0
Thesaurus C/04.6
I'm Thinking of a Number A/23.8
This Ain't Your Grandpa's Checkerboard A+/01.7
Thore's self-esteem A/05.1
Three Powers A/22.4
Game of Throwns B/02.5
Plane Ticket Pricing C/04.5
Tic Tac Toe C/14.2
Tide Goes In, Tide Goes Out D/15.2
Tight words C/23.7
Tight-Fit Sudoku E/04.2
Tildes C/02.8
Timebomb A/01.7
Stuck In A Time Loop A/01.3
Time Zones A/14.7
Timing B/34.1
Tired Terry A/03.1
Toast A/26.0
Toilet Seat A/02.2
ToLower A/01.9
Tom and Jerry C/37.2
Tomography C/04.0
Torn To Pieces C/03.5
Tower Construction A/01.7
Touchdown! A/04.2
Touchscreen Keyboard B/11.9
Tour de France B/12.9
Tourists E/13.9
A Towering Problem B/02.1
Toys A/34.2
Track Smoothing A/21.7
Train Boarding B/03.8
Train Passengers A+/01.9
Train Sorting E/05.7
Tram A/22.2
Transit Woes A/21.4
Transportation Planning C/05.1
Travel the Skies B/03.7
Treasure Diving D+/06.6
Treasure Hunt B/02.7
Treasure Map A/35.0
Treehouses C/04.0
Treequivalence E/06.4
Trending Topic B/05.5
Tri B/01.6
Sierpiński Circumference A/32.5
Triangle Ornaments A/32.1
Trick or Treat B/23.8
Trik A/01.4
Triangle Trilemma A/23.7
The Trip, 2007 B/02.9
Triple Texting A/01.6
Tri Tiling C/12.4
Trojke B/23.1
Troll Hunt A/12.4
Travelling Salesperson 2D E/01.4 - 9.5
Tunnelling the Earth A/34.3
Turbo E/04.5
Turning Trominos B/34.8
Turtle Master B/13.0
ICPC Tutorial A/22.9
Take Two Stones A/11.3
Ultra-QuickSort C/04.8
Umm Code B/13.5
UnDetected C/03.8
(un)Fair Play D/04.4
Union-Find C/05.5
Units C/13.4
Unlock Pattern A/11.7
Unlock Pattern II A/33.6
Arrangement A/11.3 - 1.8
The Ups and Downs of Investing A+/03.6
Urban Design A/34.1
Using Digits C/05.1
The Uxuhul Voting System C/13.3
Vaccine Efficacy A/12.1
Vacuumba A/11.8
Right-of-Way A/01.9
Vanishing Parentheses C/04.9
Variable Names B/06.9
Variable Arithmetic B/02.6
Vauvau A/11.8
Veci A/11.7
Boiling Vegetables B+/03.7
Victory Through Synergy E/03.9
Video Speedup A/11.9
Virtual Friends C/04.8
Virus Replication A+/03.4
VisuAlgo Online Quiz D/03.5
VivoParc E/04.8
Volim A/11.7
Popular Vote B/02.3
Vudu C/15.1
Vuk D/03.9
Waif Until Dark C/02.7
A Walk Through The Forest C/04.8
Trapezoid Walkway C/23.5
Lifting Walls B/14.3
Walrus Weights C+/03.7
Warehouse B/02.0
War on Weather A/33.5
Watchdog A/12.0
Water D/03.5
Watersheds C/03.5
Weak Vertices A/01.4
The Weight Of Words A/12.6
Welcome to Code Jam (Easy) A/02.2
Welcome to Code Jam (Hard) C/04.4
WERTYU B/02.9
Wet Tiles C/03.8
WFF 'N PROOF A+/02.8
What does the fox say? B/02.1
Wheels C/23.8
Where's My Internet?? C/03.1
Where to Live? A/14.4
Which Base is it Anyway? A/22.4
The White Rabbit Pocket Watch E/15.6
Who's the Boss? C/05.4
Wimbledon A/23.7
Wizard of Odds A/12.6
Wood Cutting C-/02.6
Wooden Signs C+/02.6
Word Cloud A+/02.4
Word Equations B+/06.7
Words for Numbers A/02.5
WordSpin C/05.3
Workout for a Dumbbell B+/05.5
Assigning Workstations B/02.8
Worst Weather Ever E/07.8
Board Wrapping E/23.6
XOR Equation A+/24.9
Yin and Yang Stones A/11.6
Yoda A/01.9
Zadaca A/13.9
Zagrade B/03.2
Zamka A/01.4
Stand on Zanzibar A/11.4
Zapis C+/14.6
Zbrka A/35.6
Zebras and Ocelots A/13.1
Zig Zag Nametag A/13.7
Zigzag A/04.9
Zipf's Law B/05.6
Zipf's Song B/24.3
Zipline A/33.4
Znanstvenik B+/03.9
Zoning C/04.9
Zoning Houses E/16.6
Un-bear-able Zoo A/01.8