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).

Problem Grade Difficulty 10 Kinds of People C/1 5.5 2048 A+/0 2.9 So you want to be a 2^n-aire? A/3 3.2 3D Printed Statues A/1 2.8 4 thought B/0 3.1 Eight Queens B/0 2.9 99 Problems A/0 2.7 A1 Paper A/1 4.1 Aaah! A/0 1.9 Abandoned Animal C-/0 5.5 ABC B/0 2.3 Ab Initio D/0 7.4 Above Average A/1 2.5 Abstract Art E/3 6.5 Abstract Painting A/2+ 5.0 Absurdistan Roads II C/3 7.0 Absurdistan Roads III D/0 5.9 Access Denied A/0 3.8 Access Points B+/3 5.9 ACM Contest Scoring A/0 1.7 Association for Computing Machinery A/1 2.7 The Calculus of Ada C/1 2.3 Add 'Em Up! B+/2 4.9 Adding Words B+/0 3.7 Add Two Numbers A/0 1.4 Adjoin the Networks D/1 5.9 Administrative Difficulties B/0 6.1 Ads C/0 4.6 Adventures in Moving -- Part IV C/0 5.2 Agamemnon's Odyssey C/0 4.1 AI Jeopardy B/2 7.1 Air Conditioned Minions D/0 3.1 Airline Hub A/3 7.0 Akcija B/0 2.2 Alchemy 101 A/2 4.0 Alehouse D/1 5.1 Alex and Barb A/2 3.6 Alice in the Digital World A+/0 4.1 Alien Integers A/1 5.8 Alien Numbers A/2 2.1 All about that base A/2 2.6 All Different Directions B/2 2.4 All is Well D/1 6.4 Alloys A/1 3.8 All Pairs Shortest Path D/0 5.0 Almost Perfect A/3- 3.2 Almost Union-Find D+/0 6.1 Alphabet B/0 3.3 Alphabet Animals B/0 4.3 Alphabet Spam A/0 1.5 Alto Singing A/2 6.0 Amanda Lounges C/0 5.7 A Mazing! C/0 5.3 Sheba's Amoebas C-/0 1.8 Amsterdam Distance A/1 2.7 A Multiplication Game A/2 4.0 Anagram Counting B/2 3.3 Andrew the Ant B-/2 5.3 A New Alphabet A/0 1.7 Alternative Anagram B/1 6.3 Annoyed Coworkers B/1 2.9 Another Brick in the Wall A/1 2.1 Another Candies A/1 2.8 Antenna Placement D/0 7.3 Anthony and Cora C/2 5.2 Anthony and Diablo A/1 2.9 Ocean's Anti-11 A/2 2.8 Ocean's Anti-11 (Hard) E/2 7.9 Antiarithmetic? A/3 7.2 Ants A/1 2.4 Ant Typing E/2 6.1 Apaxiaaaaaaaaaaaans! A/0 1.4 Honour Thy (Apaxian) Parent A/0 1.6 A+B Problem E/3 8.2 Appalling Architecture A/1 4.2 Appeal to the Audience C/0 5.6 Falling Apples A+/0 3.2 Johnny Applesack C/1 3.4 A Prize No One Can Win B/0 2.5 Aqueduct Construction E/1 6.0 Arachnophobia D/0 5.0 Arbitrage? D/1 4.1 Architecture A/0 2.7 Arctic Network D-/0 4.7 A Real Challenge A/1 1.6 Are You Listening? B/1 2.5 Arithmetic A/2 4.2 Arithmetic Decoding B/2 2.3 ARMPIT Computations C/1 5.1 Army Strength (Easy) A/0 2.3 Army Strength (Hard) A/0 2.1 Array of Discord A/0 5.2 Amalgamated Artichokes A/1+ 2.6 Artwork C/2 5.5 ASCII Addition A/0 2.0 ASCII Figure Rotation A+/0 3.1 Ask Marilyn A/2 4.8 Assassins C/2 7.0 Association of Myths A/2 5.5 Associative Exponents A/2 4.0 Asteroid Mining E/0 8.2 Astro A/3 3.9 Astrological Sign A/0 2.3 Autori A/0 1.3 Average Character A/0 1.9 Paradox With Averages A/1 2.9 Paradox With Averages (Hard) A/1 2.9 Average Speed A/1 3.4 Avion A/0 1.4 AVL++ C/3 5.2 Avogadro A+/0 5.8 Avoidland A/2 3.2 Awkward Party B/0 2.9 BAAS C/0 5.5 Babelfish B/0 2.6 Baby Bites A/0 1.9 Babylonian Numbers A/2 2.1 Baby Panda A/1 2.2 Bachet's Game C/2 3.4 Backpack Buddies D/1 6.9 Backspace B/0 2.1 Bacon, Eggs, and Spam B/0 1.8 Bag of Tiles D/2 6.1 Balanced Diet C/0 3.8 Ball Bearings B/1+ 4.1 Ball Colors A/3 5.4 Distributing Ballot Boxes B+/1 4.4 Balls and Needles C/0 3.9 Baloni C/0 3.5 Banana Problem B+/1 6.1 Bank Queue B/0 3.0 Bar Classification B/0 4.1 Barcode B/3 6.9 Bard B/0 2.7 Barica C+/0 6.5 Bar Shelf E/0 1.4 - 7.6 Base-2 Palindromes A/2 4.4 basic E/1 8.0 BASIC Interpreter E/0 5.7 Basic Programming 1 A+/0 3.8 Basic Programming 2 B/0 3.4 Basic Remains A/1 3.2 Basketball One-on-One A/0 1.6 Batmanacci B/3 3.1 Exploding Batteries C/0 3.8 Batter Up A/1 1.3 Battle of Hogwarts D/0 6.0 Battleship C/0 4.5 Battle Simulation A/0 3.0 Baza B+/0 5.7 Bazen A/1+ 2.4 Beast Bullies A+/0 5.8 Beat the Spread! A/1 2.4 Beautiful Primes A/2 4.4 Beautiful Square A/0 6.1 Beavergnaw A/1 1.7 Beehives A/1 2.1 Beehives D/0 5.2 Bee House Perimeter C/3 3.7 Beekeeper A/0 2.6 Collecting Beepers C/0 4.8 Bee Problem C/3 4.3 Bela A/0 1.4 Bell Ringing A/3 4.7 Best Before A/1 3.8 Best Compression Ever A/2 2.4 Best Rational Approximation A/3 5.0 Best Relay Team B/0 1.9 Betting A/0 1.3 Bicikli C/0 6.4 Big Boxes B/0 3.4 The Biggest Triangle A/3 4.7 Big Truck C+/0 3.3 Bijele A/0 1.4 Bike Gears B/1 5.1 Bilateral Projects C/0 6.1 Billiard A/1 1.8 Bing It On B/0 3.4 Bio Trip D/1 6.9 Bird Rescue D/1 5.4 Birds on a Wire A/1+ 3.3 Birthday Party D/0 3.1 Birthday Boy B/1 4.5 Birthday Paradox A/3 5.8 Bishops A/2 2.3 Bit 4 Bit D/0 7.4 Bit by Bit A/2 3.0 Bitmask A/0 3.6 Bits B/1 2.5 Bits Equalizer A/2 3.8 Black Friday B/0 2.3 Black Out A/2 3.4 Block Crusher C/1 3.3 Block Game A/2 3.4 Blocks on Blocks E/3 6.0 Blåtand A/0 1.4 - 1.9 Boat Parts B/0 1.6 Bobby's Bet A/3 2.8 Boggle B/0 4.5 Accounting B/0 3.9 Bond E/2 5.8 Book Circle D/0 5.6 Book Club C/0 5.2 Booking D/1 5.6 Booking a Room B/0 1.7 Bootstrapping Number B/0 2.8 Borders D/0 7.1 Boss Battle A/1 1.9 Bottled-Up Feelings A+/3 2.4 Curvy Little Bottles B/3 3.0 Bounding Box A/3 3.6 Bounding Robots A/2 1.7 Bowser's Pipes C/0 6.4 Boxes D/0 4.0 Alternative Bracket Notation C/0 5.4 Bracket Pairing C/0 6.0 Bracket Sequence B+/0 5.1 The Board Game D/0 4.0 - 4.1 Bread Sorting A/3 5.0 Bread Pit C+/1 7.0 Breaking Bad C/0 3.9 Breaking Branches A/0 1.6 Breaking Cake C/0 5.7 Letter Optimization C/0 1.3 - 5.1 Brexit C/0 2.9 Brexit Negotiations D/0 5.3 Bridges and Tunnels C/0 3.2 Brocard Point of a Triangle D/3 3.9 Broken Calculator A/0 2.7 Broken Swords A/1 1.8 Brownie Points I B/1 2.3 Bridges D/0 1.4 - 2.5 Binary search tree B+/0 7.0 Delicious Bubble Tea A/1 2.6 Bucket Brigade A/1 3.9 Build Dependencies C/0 3.9 Building Boundaries A/1 3.7 Buka A/0 2.0 Bumped! D/0 4.2 Bungee Builder A+/0 3.4 Bungee Jumping A/3 4.8 Burizon Fort B/2 5.3 Burrows-Wheeler E/0 6.5 Bus A/1 1.6 Bus Lines A/1 2.6 Bus Numbers A/0 2.5 Bus Numbers B/1 2.8 The Bus Card A/1 1.3 - 2.6 Bus Ticket C/1 5.3 Busy Schedule A/1 2.4 Button Bashing C/1 3.4 Buzzwords E/0 5.3 Cake A+/0 5.3 Cakey McCakeFace B+/0 4.0 Calculating Dart Scores B/0 3.3 Calculator E/0 3.2 Calories From Fat A+/1 2.1 Camp Lunches C/1 5.1 Canadians, eh? A/0 1.6 Candle Box A/2 2.5 Candy Distribution A/3 4.7 Candy Division B/3 4.1 Canonical Coin Systems D/0 4.8 Cantina of Babel D/1 3.0 Cantor A/2 2.9 Canvas Painting E/0 3.6 Canvas Line A+/0 4.9 Canyon Crossing D/0 6.8 Cardboard Container A/2 2.5 Card Divisibility A/2 4.5 Card Hand Sorting D/0 4.2 Card Hands B/0 5.7 Card Magic C/1 3.9 Card Trading B/0 2.7 Card Trick B/0 1.8 Careful Ascent A/1 2.1 Carousel Rides B/1 2.6 Solving for Carrots A/0 1.4 Car Trouble C/0 4.3 Cash Transport B+/0 4.6 Catalan Numbers A/2 4.0 Catalan Square A/2 3.1 Catching Noodles C+/2 8.1 Catenyms D/0 7.0 A Feast For Cats C/0 3.6 Advanced Causal Measurements E/2 7.0 Cave Exploration D/0 3.8 Cave Exploration C/0 3.8 CD B/0 5.2 CDVII B/0 6.0 Ceiling Function B/0 2.1 Cent Savings D/1 5.1 Opening Ceremony B/1 3.0 Cetiri A/1 1.7 Cetvrta A/0 1.4 Chair Hopping A/3 5.6 Champernowne Count A/1 3.0 Chanukah Challenge A/1 1.4 Character Development A/2 2.2 Charged A/1 2.1 Charles in Charge C/0 5.4 Charting Progress B/0 2.0 Chatter C/0 4.6 Cheating at War E/0 5.6 Cheating a Boolean Tree D/0 4.5 Checking Break A+/2 6.2 Checking For Correctness A/2 3.8 Checkmate in One A/0 4.6 Cutting Cheese B+/1 3.0 Cheese, If You Please E/1 3.5 Chemist's vows E/0 3.1 Chess A/2 2.9 Chess Competition D/0 7.0 Chess Tournament C/0 6.0 Chewbacca B/2 3.2 Chinese Remainder A/3 5.1 Chocolate Division A+/0 2.0 Preludes A/0 1.8 Chopping Wood B/3 3.1 Cinema Crowds A/0 2.2 Cinema Crowds 2 A/0 1.8 Cinema Seating B/0 2.7 Circuit Math B/0 2.0 Circular DNA C/1 3.3 Circumsphere A/3 4.9 The Citrus Intern C/1 3.6 Class Picture B+/0 5.4 A Classy Problem B/0 4.4 Cleaning Pipes E/2 5.4 Climbing Stairs A/1 3.8 Climbing Worm A/2 2.4 Clinic B+/1 3.9 Clock Construction B/0 4.4 Clock Pictures E/1 4.8 Closest Pair (Uniform) E/2 6.4 Closest Sums B/1 2.5 Closing the Loop A/1 1.7 Coast Length C/0 3.4 A Furious Cocktail A/0 2.4 Cocoa Coalition A/2 4.8 Coconut Splat B/0 1.5 Code Cleanups A/1 2.8 Code Guessing A/0 3.0 Code Names D/3 5.3 Code to Save Lives A/1 1.6 Coffee Cup Combo A/0 1.6 Coffee Date D/2 5.0 Coin Stacks B/0 4.0 Cokolada A/2 2.2 Cold-puter Science A/0 1.4 Collapse C/0 3.3 Collatz Conjecture A/1 4.2 Collatz Conjecture D/2 7.5 Coloring Socks B/1 2.4 Coloring Graphs B+/0 5.5 Colorland A+/0 4.1 Colourful New World C/0 5.8 Colour Wars B/0 3.2 Combination Lock A/2 3.0 Combinatorial Stanley Cup A/2 3.0 Comma Sprinkler C/0 4.4 Radio Commercials B/0 1.8 Committee Assignment E/3 7.2 Common Factors A/3 5.1 Jumbled Communication A/1 2.1 Communications Satellite C/2 3.7 Jumbled Compass A/1 2.1 Competitive Arcade Basketball B/0 2.4 Completing the Square A/2 1.9 Compositions C/1 2.4 Compound Words A/0 1.8 Best Compromise A/1 2.1 Concentration A+/0 5.2 Conformity B/1 1.5 Conga Line B/0 1.2 - 3.7 Connect-N B/0 3.6 Connect the Dots A/0 3.7 Conquest B/0 3.2 Conquest Campaign C/0 2.2 Sums A/3 3.5 Conservation D/0 4.7 Constrained Freedom of Choice D/0 4.8 Multi-Year Contest Scheduling C/0 5.0 Contest Struggles A/1 2.2 Continuous Median B+/0 3.4 Association for Control Over Minds B/0 4.2 Cryptographer's Conundrum A/0 1.4 Conversation Log B/0 2.9 Convex Polygon Area A/3 1.9 Cookie Cutters A/3 2.4 Cookie Selection B+/0 4.8 Cooking Water A/1 1.9 Cops and Robbers D/0 4.6 Costume Contest A/0 1.9 Circuit Counting C/0 5.8 Counting Chocolate A/0 4.4 Counting Clauses A/0 1.6 Counting Greedily Increasing Supersequences B+/3 6.4 Counting Stars B/0 3.0 Counting Triangles A/3 2.3 Count the Vowels A/0 1.3 Course Scheduling B/0 1.8 Cow Crane C/0 3.6 Cpr-nummer A/0 1.4 Exploding CPU A/3 6.1 Cracker Barrel Game C/2 4.3 Cracking RSA A/2 2.2 Cracking the Code B+/0 5.4 Cranes B/1 3.9 Crashing Robots B/0 4.0 Credit Card Payment A/1 5.3 Cribbage On Steroids B/2 4.4 Criss-Cross Cables B+/0 5.9 Crne A/2 2.5 Crop Triangles (Easy) B/2 3.2 Cross B+/0 4.0 Cross Country C/0 2.9 Crowd Control D/1 3.7 Cryptographic Keys A/2 4.2 Cu Chi Tunnels B/2 3.0 Cudoviste A/0 1.4 Stacking Cups A/0 1.6 Curse the Darkness A/1 2.6 Curveknights C/1 3.0 Stacking Curvy Blocks A/2 4.8 Cut in Line B/0 1.6 Cutting Brownies E/1 4.2 Cutting Corners A/3 2.9 Cutting the Necklace B+/0 5.8 Cyanide Rivers A/0 2.3 Cycles (Easy) D/2 4.2 Daily Division E/0 5.7 Damaged Equation A/0 2.3 Dams in Distress B+/0 3.7 Dance Recital E/0 3.5 Dangerous Skiing C+/1 8.8 The Darkness C/0 8.3 Dartboard A/2+ 4.5 Darts A/1 2.5 Dart Scoring B/3 4.4 Das Blinkenlights A/1 1.7 DA-Sort B/0 3.0 Big Data D/2 5.9 Dating time A/2 4.3 Datum A/1 1.5 Dead-End Detector C+/0 3.8 Dead Fraction A/2 5.2 Death Knight Hero A/0 1.6 Deathstar A/1 1.8 Death and Taxes A/1 2.9 Deceptive Dice C/1 3.4 Decisions, Decisions B/1 3.1 Deduplicating Files B/2 3.9 Delimiter Soup B/0 2.1 Postal Delivery C/1 2.9 Destination Unknown D/0 4.4 Detailed Differences A/0 1.4 Detour C/0 4.8 DEX Save B/2 4.6 Diagonal Cut A/3 3.6 Dice and Ladders B+/3 8.1 Dice Betting C/2 4.4 Dice Cup A/1 1.4 Dice Game A/1 1.6 A Different Problem A/1 2.6 Different Distances A/1 1.7 Digbuild B/3 4.5 Digi Comp II C/1 5.8 Digits A/1 3.4 Digit Sum A/2 6.7 Digit Swap A/0 1.3 Dirty Driving B/0 2.4 Disastrous Doubling A/1 4.0 Discrete Logging B/3 4.5 Disgruntled Judge A/3 3.8 Digital display A/0 2.3 Distance B/1 4.2 Distributing Poffins A/1 2.2 Divide and Conquer A/3 7.9 Divide by 100... A/1 4.4 Divisible Subsequences B/3 3.5 Divisors A/3 5.9 Divisor Shuffle A/2 4.8 Divvying Up A/1 1.6 DNA A+/0 4.3 Dobra C/1 3.6 Doctor Kattis E/1 3.9 Dodecaphony A/2 3.4 Dog & Gopher A/1 2.6 Dominating Duos C/0 7.6 Dominoes 2 C/0 3.5 Dominos C/0 4.7 Don't Fence Me In C/3 4.8 Doorman B/0 2.2 Double Dealing C/3 6.8 Double Password A/1 1.6 Doubleplusgood A/0 2.6 Doublets D/0 8.2 Disastrous Downfall C/0 4.6 Disastrous Downtime C/0 3.2 Draft Time C/0 8.1 Dragon Ball I E/0 5.4 Dragon Balls A/1 5.3 Draughts C/0 4.4 Dreamer E/1 2.2 Drinking Song A/0 2.3 Drink Responsibly C/1 4.7 Driver's Dilemma A/1+ 2.2 Xtreme Driving E/3 4.8 Driving Lanes D/1 3.5 Driving Range C/0 3.5 DRM Messages A/1 1.5 Dropping Directions C+/0 3.6 Drunk Vigenère A/1 1.6 Daylight Saving Time A/1 2.3 Dual Divisibility A/2 4.5 Dungeon master C/0 3.8 Dunglish B/2 2.9 RA Duty Scheduler C+/0 3.9 DVDs A/2 2.9 DVD Screensaver A/3 6.9 Dyslectionary A/0 3.2 Early Winter A/0 1.7 The Easiest Problem Is This One A/0 1.6 Easter Eggs C+/1 5.3 As Easy as CAB C+/0 8.8 Eating Everything Efficiently C/0 4.3 Eating Out A/2 4.0 Echo Echo Echo A/0 1.3 Eco-driving D/2 6.1 Edge Removal D/0 5.5 Eeny Meeny B/0 1.8 Egypt A/1 2.2 Eidam-Sand Lair A/0 5.7 Eko B/0 4.7 Elder Scrollbar A/0 6.0 Election B/0 2.5 Election Paradox A/0 1.8 Electrical Outlets A/0 1.4 Elementary Math C/1 5.0 Elevator Trouble C/0 2.8 Eligibility A/0 1.6 Emergency Contest Running A/2 3.8 Emergency Exit C/0 6.0 Emag Eht Htiw Em Pleh A/0 1.7 Encoded Coordinates B/3 6.4 Encoded Message A/0 1.5 Endless Knight D/3 6.5 The End of the World B+/2 4.5 Escape from Enemy Territory C+/0 4.4 Engineering English B/0 2.2 Enlarging Hash Tables A/2 3.3 Entering the Time C/1 5.2 Enumerating Brackets C+/0 6.6 Envious Exponents A+/3 5.0 EpigDanceOff A/0 2.1 Equal Sums (Easy) C-/1 2.4 Equations A+/2 6.4 Equilibrium Mobile B+/1 3.8 Proving Equivalences D/0 6.1 Erase Securely A/1 1.6 Erdős Numbers B/0 5.3 Errands D/0 6.2 Erratic Ants C/0 5.0 Escape Plan C/1 5.6 Escape Wall Maria C/0 3.6 Esej A/0 3.1 Espresso! A/1 2.1 Espresso Bucks B/0 2.1 Estimating the Area of a Circle A/1 1.5 Eternal Embers C/0 6.4 Euclidean TSP D/1 2.2 Euclid's Game A+/3 4.2 Eulerian Graphs D/0 3.0 Eulerian Graphs 2 B+/0 3.6 Eulerian Path D/0 5.6 Euler's Number A/2 2.4 European Trip A/3 3.4 Evening Out 1 A/1 3.1 Event Planning A/1 2.1 Even Up Solitaire B/1 2.6 Everything Is A Nail C+/2 5.2 I've Been Everywhere, Man A/0 1.4 Exact Change C/0 3.8 Exactly Electrical A/2 2.1 Exam A/2 1.9 Exam Manipulation A/0 5.2 Excavator Expedition C/0 5.4 Excellent Engineers B+/0 5.9 Exchange Rates C/1 5.3 Exchange Students B+/0 7.4 Kindergarten Excursion A+/0 3.7 Exits in Excess C+/0 4.1 Exoplanet Lighthouse A/1 2.6 Expanding Rods B/2 6.6 Expected Earnings A/1 1.8 Expeditious Cubing A/2 4.7 Eye of Sauron A/0 1.4 Factorial Power A/3 6.3 Factors C/3 5.7 Factovisors A/3 6.2 Factstone Benchmark A/3 3.7 Fair Division C/1 3.3 Fair Play B/1 3.5 Fair Warning A/2 5.2 Fake News! A+/0 6.1 Faktor A/1 1.4 Falcon Dive A/0 3.3 Falling Mugs A/2 4.6 Falling Apart A/1 1.7 False Sense of Security A/0 2.0 Fantasy Draft B/0 4.1 Farey Sequence Length A/3 3.6 Farming Mars C+/0 6.2 Fast Food Prizes A/0 2.1 Faulty Robot C/0 4.0 A Favourable Ending C/0 4.7 FBI Universal Control Numbers A/1 2.2 Feistel Fun B/3 8.3 Fence Bowling B/2 3.2 Fenwick Tree E/0 4.2 Ferry Loading C/0 6.9 Ferry Loading III B/0 4.7 Ferry Loading IV B/0 2.6 Fiat A/3 5.7 Fibonacci Cycles B/1 3.1 Minimal Fibonacci Sums A/1 2.3 Fibonacci Tour C/1 5.4 Field Trip A/0 2.5 Fifty Shades of Pink A/0 1.5 Filip A/0 1.3 Final Exam A/0 1.7 Financial Planning B/1 3.6 Finding An A A/0 1.3 Find my Family B+/0 4.0 Find Poly C/2 3.1 Find the Graph C/0 3.5 Fire C/0 4.2 Firefly C/0 3.1 Firetrucks Are Red C/0 4.4 Fishmongers B/1 3.7 FizzBuzz A/1 1.4 FizzBuzz A/0 3.2 Flag Quiz A/1 3.3 A Flea on a Chessboard A+/2 6.0 Flexible Spaces A/0 1.7 Flight Collision B/1 6.8 Flight Plan Evaluation B/3 5.7 Flip Five C/0 3.1 Flip Flow A/0 2.0 Flipping Cards E/0 6.8 Flipping Patties A/0 2.3 Floating Formation E/0 5.6 Flooding Fields C+/1 6.8 Flood-It C/0 4.0 Floor Plan A/2 4.0 Floppy Music C/0 5.3 Flower Garden A/2 4.0 No Trees But Flowers A/2 6.2 Flowery Trails C/0 3.7 Flow Layout A/0 1.9 Flow Shop C/0 2.5 Fluortanten A/1 1.2 - 2.3 Flygskam C/2 4.3 Flying Safely A/2 1.7 Birthday Memorization B/0 1.2 - 1.7 Folded Map E/0 4.7 Folding a Cube C/2 5.5 Font D/2 4.0 Fountain C/0 2.2 Fooling Around C/2 5.5 Foosball Dynasty B/0 4.0 Forced Choice A/0 1.5 Forest Fires C/0 5.3 Forest Fruits C+/0 4.2 Forests B/0 3.6 Fractal Area A/2 2.7 Continued Fraction A/2 3.8 Fractional Lotion A/2 2.9 Freckles C/0 4.7 Free Food A/0 1.6 Free Weights B+/0 4.2 Friday the 13th A/1 2.0 Fridge A/1 3.2 Frogger C/2 5.3 Froggie A/0 6.1 From A to B A/0 2.4 Frosh Week C/0 5.6 Frosh Week B/0 2.2 Frosting on the Cake A/2 3.5 Frozen Rose-Heads B/0 5.4 Fruit Baskets C/2 4.3 Frustrated Queue C/0 4.1 Functional Fun A/1 1.9 Fundamental Neighbors C/2 4.3 Fun House B/0 1.9 FYI A/0 1.3 Galactic Warlords B/2 6.8 Game Night D/1 5.0 Game of Cards E/2 5.2 Game Rank A/0 3.6 Game Suggestions C/0 4.1 Gandalf's Spell B/0 2.1 GCD A/1 1.8 GCDs D/2 5.0 Galactic Collegiate Programming Contest B+/0 4.5 GCVWR A/0 1.4 Gear Changing A/1 3.4 Gears C/1 3.6 Geezer Scripts C/0 2.5 Genealogical Research B/0 3.8 Gene Block A/1 2.1 Chinese Remainder Theorem (non-relatively prime moduli) A/3 3.9 Generalized Recursive Functions C/1 4.4 Genetic Search B/0 2.1 Genius C/1 2.6 George D/0 2.1 Geppetto C/2 2.6 Gerrymandering A/1 1.6 Get Shorty C/0 3.6 Getting Through C+/1 5.7 Get to Work B/0 2.5 Ghostbusters 3 A/3 3.2 Ghost Leg A/0 1.4 Gig Combinatorics A/2 4.1 Glasses Foggy, Mom's Spaghetti A/1 1.9 GlitchBot A/0 2.0 Glossary Arrangement C+/0 4.4 Glyph Recognition A/2 2.5 Goat Rope A/1 1.6 Goat Ropes E/1 7.3 Going to Seed B+/0 5.7 Getting Gold C/0 2.3 Goldbach's Conjecture A/2 2.2 Golomb Rulers B/0 3.0 Good Coalition C/1 4.1 Good Messages A/0 5.2 Good Morning! A+/0 2.9 Goofy Geometry A/2 5.2 Gopher II C/0 4.7 Gorillas A/3 6.3 The Gourmet C/0 2.2 - 2.5 Grade Curving A/1 4.6 Grading A/0 1.6 Grand Opening D/0 6.3 Grandpa Bernie B/0 2.8 Granica A/2 6.1 Through the Grapevine C/0 3.7 Watering Grass D/1 5.3 Gregory the Grasshopper C/0 3.8 Grass Seed Inc. A/1 1.4 Gravity C/0 4.2 Grazed Grains A/1 3.1 GREAT + SWERC = PORTO C/0 3.9 Greedily Increasing Subsequence A/0 2.2 Greedy Polygons A/1 1.6 Greedy Polygons Revisited B/3 5.6 Green Eggs and Ham E/0 8.1 Greeting Card B/2 4.4 Greetings! A/0 1.3 Grid C/0 2.7 Grid Game C+/0 5.1 Grid Magic A+/1 2.6 What's on the Grille? A/1 3.7 Groupthink A/2 5.0 Guardian of Decency C/0 5.9 Guess the Number B/0 3.1 Guessing Game A/2 3.0 I Can Guess the Data Structure! B/0 3.2 Gwen's Gift B/3 5.3 Haiku E/0 5.3 Watch Out For Those Hailstones! A/0 2.7 Half a Cookie A/1 1.8 Hall O' Wee Mirrors A/3 5.2 Hamming Ellipses C/1 3.4 Hanging Out on the Terrace A/0 1.6 Hangman A/0 1.6 Happy and Unhappy Numbers C/0 6.1 Happy Happy Prime Prime A/2 2.2 Hard Drive A+/0 3.5 Hardware B/1 2.0 Hardwood Species B/1 2.7 Harshad Numbers A/1 1.5 Haughty Cuisine A/0 1.6 Haunted Graveyard D+/0 7.5 Hay Points B/0 1.9 Head Guard A/0 2.1 Heart Rate A/1 1.4 Heating Up C+/0 7.0 Height Ordering A/0 2.1 Homework A/0 1.1 - 1.5 Heir's Dilemma A/1 1.7 Heliocentric A/2 1.9 Hello World! A/0 1.1 Government Help A+/2 6.6 Help a PhD candidate out! A/0 1.7 Helpful Currents C/0 6.5 Help Me With The Game A/0 2.9 What Does It Mean? C/2 5.0 Herkabe D/2 5.7 Herman A/1 1.7 Hermits B+/0 3.4 Hidden Password B/0 2.3 Hiding Places C/0 1.7 Highway to Mount Fansipan B/2 3.8 H-Index A/0 4.0 Hissing Microphone A/0 1.4 Historic Exhibition B/0 4.1 Hitting the Targets A/1 1.6 Semi-prime H-numbers A/3 5.2 Hogwarts C/0 6.0 Holey N-Queens (Batman) B+/0 2.4 Holiday Stars A/3 5.8 Honeycomb Walk C/0 2.7 Honey Heist C/1 3.7 Honi C/0 3.7 Hopscotch A/3 5.6 Hopscotch 50 C/0 3.0 Horror List C/0 2.9 Horror Film Night C/0 3.5 Hotels C+/2 7.4 Hot Hike A/0 2.0 Hot Spot C/0 5.9 Hot Springs B/0 2.5 House Lawn B/1 3.7 House of Cards A/1 3.4 Howl A/0 2.0 How Many Digits? A/2 3.5 How many 0's? A/2 4.1 H to O B/1 2.7 Huge Campus D/0 4.5 Human Cannonball Run C/1 1.9 The Amazing Human Cannonball A/1 1.5 Hunt the Wumpus A/0 2.4 Hurricane Danger! A/3 5.0 Hyacinth C/0 5.1 Hydra's Heads A/2 1.8 Hamiltonian Hypercube A/2 3.2 Pascal's Hyper-Pyramids B/3 4.7 iBoard A/1 2.4 Ice Cream C+/1 5.6 I Could Have Won A/0 3.1 ICPC Awards A/0 1.6 ICPC Team Selection A/1 3.1 An I for an Eye A+/0 4.3 if-then-else E/0 7.6 Ignore the Garbage A/1 3.0 Igra B+/0 6.4 Iks B/2 3.3 Illiteracy C/0 3.2 Illuminati Spotti A/0 1.9 Image Compression B/0 7.2 Image Decoding A/0 3.3 Image Processing A/0 2.0 Imperfect GPS A/2 4.0 Import Spaghetti D/0 5.4 #include<scoring> B/1 4.2 Incognito A/2 3.1 Increasing Subsequence D/0 4.1 An Industrial Spy E/2 2.9 Infinite 2D Array A/3 5.2 Infinite Slides B+/3 3.2 In Flagrante Delicto D/0 4.6 Inflation A/1 1.8 A Question of Ingestion C/0 5.8 Inquiry I A/0 2.6 Tree Insertion A/2 2.2 Inspecting Illumination A+/2 5.3 Integer Division B/2 3.5 Integer Lists A+/0 5.3 Intergalactic Bidding A/2 3.6 Interpreter A/0 3.6 Interval Cover D/0 5.3 Interval Scheduling B/0 1.9 Inventing Test Data C+/0 5.1 Inverse Factorial B/2 5.7 Inverted Deck B/0 4.0 Invoker (Easy) A/1 2.3 Invoker (Hard) A/2 3.6 IOU C/0 5.2 I Repeat Myself I Repeat Myself I Repeat A/0 2.2 Iron and Coal D+/0 5.0 Irrational Division C/1 4.6 Is It Even? A/1 3.2 IsItHalloween.com A/0 1.5 Island Buses C/0 7.1 Island Hopping C/0 2.7 Islands in the Data Stream B/0 3.2 Islands C/0 1.8 God Save the i-th Queen D/0 6.4 It's a Secret A/0 6.4 I Wanna Be The Very Best A/0 2.7 Jabuke A/3 1.8 Jack-O'-Lantern Juxtaposition A/1 1.3 Jackpot A/2 3.5 Jack The Lumberjack B/1 6.7 Jailbreak D+/0 5.1 Jane Eyre B/0 4.6 Janitor Troubles B/3 1.5 Jazz it Up! A/1 2.2 Jet Set A/1 4.2 Jewelry Box A/2 1.7 Jigsaw A/1 4.7 Job Switching A/3 2.6 Job Expenses A/0 1.5 Chicken Joggers C/0 5.7 Join Strings B+/0 3.4 Joint Attack A/1 2.7 Joint Jog Jam A/1 1.7 Jolly Jumpers A/0 3.6 Joyless Game A/1 4.0 Judging Troubles B/0 3.0 Judging Moose A/1 1.5 Juggling Patterns A/1 5.9 Jug Hard A/2 2.9 Juice C/0 5.3 Julemost B/1 2.2 - 2.4 Jumbo Javelin A/0 1.3 Jumping Yoshi C+/0 5.5 Space Junk A/2 4.3 Jupiter Orbiter C/0 6.1 Jurassic Jigsaw C/0 2.5 Jury Jeopardy C/0 2.3 Just a Minute A/1 1.8 Just Enough Water B/0 4.5 Just for Sidekicks E/0 3.6 Just Passing Through C+/0 5.0 Kafkaesque A/0 2.0 Kaleidoscopic Palindromes A/2 3.1 Kapløb B/0 2.1 - 2.4 Karte A/0 1.6 Kastenlauf C/0 3.5 Kattis's Quest B/0 4.1 Kayaking Trip B+/0 3.6 Keep Him Inside A/3 7.5 Keep it Cool B+/0 2.7 Kemija A/0 1.8 Keyboards in Concert D/0 3.2 Keyboardd B/0 2.6 Tastelogger A/0 1.3 - 2.5 Matrix Keypad A+/0 3.3 The Key to Cryptography A/0 1.7 Keywords B/0 2.3 Killing Chaos B+/0 5.8 K-In-A-Row A+/0 4.2 King of the Waves C/0 5.0 King's Colors A/3 4.5 Kitchen Measurements C/0 3.6 Kitchen Combinatorics B/2 5.3 Kitten on a Tree B/0 1.7 Kleptography A/1 1.5 The Clock A/1 1.5 - 1.7 Knapsack C/0 4.7 Knapsack Packing C+/0 5.2 Knight Jump C/0 2.4 Knight Packing A+/0 1.3 Knight Search C/0 3.6 Knights in Fen C/0 3.6 Knigs of the Forest B/0 4.0 Knitpicking B/0 2.7 Knot Knowledge A/0 1.5 Codforces A+/0 1.4 - 5.7 Kolinje A+/1 6.0 Kolone A/0 2.7 Consulting Gigs C+/0 5.3 Buying Books B/0 2.5 - 4.0 Kornislav A/1 1.5 Križaljka A/0 1.8 Kutevi A/1 2.7 Ladder A/1 1.6 Ladice C+/0 3.8 Lamps A/1 1.3 - 2.6 Land Equality A/0 5.4 Landlocked D/0 5.6 Landscape Generator B/0 3.1 Laptop Sticker A/0 1.5 Laptop Stickers A/0 2.5 Largest Hoarding B+/0 4.3 Last Factorial Digit A/1 1.5 Last Minute A/1 2.3 Lava C/1 6.0 Lawn Mower A/1 2.0 Learning to code E/0 8.5 Left and Right A/0 3.0 Left Beehind A/0 1.7 Lektira B/0 2.7 Lemonade Trade C/1 5.9 Less vs. Fewer A/0 2.0 License to Launch A/0 1.6 Limbo: Part 1 A/2 4.2 Limbo: Part 2 A/2 4.7 Linden Mayor System B/0 2.3 Linear Recurrences B/3 5.1 Line Them Up A/0 1.8 Lipschitz Constant B/2 4.4 Liquid Assets A/0 3.4 Listen To Your Boss D/0 4.5 A List Game A/2 2.9 Litespace E/1 5.1 Locked Treasure A/2 2.4 Locust Locus A/1 2.0 Logo A/1 2.6 Longest path in a DAG C/0 5.0 Longest Prime Sum A/1 2.1 Longest Increasing Subsequence D/0 5.5 Long Swaps A/2 3.5 Loopy Cab Drivers D/0 6.8 Loopy Transit C+/2 3.6 Loo Rolls A/1 1.7 The Dragon of Loowater A/0 2.7 Lost In The Woods A/3 3.8 Lost Lineup A/0 1.6 Lost Map C/0 2.5 Low Order Zeros A/3 4.2 ls C/0 5.2 Lucky Numbers C/2 4.1 Luhn's Checksum Algorithm A/1 1.7 LumberCraft B+/1 5.2 Keystrokes B/0 1.1 - 5.6 Mafija D/0 6.2 The Magical 3 A/2 5.8 Magical Cows A+/1 4.6 Association of Cats and Magical Lights E/2 5.7 Magical Runes A/1 3.3 Magic Sequence D/0 7.5 Magic Trick A/0 1.4 The Mailbox Manufacturers Problem C/0 2.0 Majstor A/0 2.4 Making A Meowth A/1 1.6 Malfunctioning Robot A/1 3.2 Mali B+/0 6.0 Mall Mania C+/0 5.2 Mancala A/0 1.8 Mandelbrot A/1 3.1 Manhattan Mornings E/0 5.1 Identifying Map Tiles A/1 1.6 Marbles On A Tree C/0 2.9 March of the Penguins D/1 4.2 Marko A/0 1.9 Mars Window A/1 2.2 Mars-DNA A+/0 1.3 - 3.5 m-ary Partitions C/1 3.6 Massive Card Game B+/0 2.9 Mastering Mastermind B/0 2.5 Match Game A/0 4.8 Matchsticks A/2 4.2 Mathemagicians A/0 5.1 Math Homework A/2 1.9 Math Trade C/0 3.4 Math Worksheet A/0 5.7 Matrix Inverse A/2 3.0 Maximum Number of Colinear Points B/2 4.8 Maximum Flow C+/0 4.6 Maximizing (And Minimizing) Your Winnings C/0 4.1 Maximizing Your Pay D/0 5.6 Maximum Rent A/3 3.1 The Maze Makers C/0 3.0 Maze Movement C/1 3.6 Imperial Measurement A/1 2.0 Meeting Points A/3 6.6 Mega Inversions E/1 3.2 Three-State Memory A/3 7.9 Memory Match A/2 4.1 Menu Updates B/0 4.8 Meow Factor A/2 3.2 Messages from Outer Space C/0 4.8 Metaprogramming B/1 2.1 Methodic Multiplication A/0 1.6 Mia A/1 2.0 Milestone Counter B/1 3.2 Millionaire Madness D/1 2.5 Minimum Cut C/0 3.9 Minecraft Dungeons C/0 5.6 Mini Battleship B+/0 4.5 Minimum Scalar Product A/1 2.5 Minor Setback B/1 3.5 Minesweeper Squared A+/2 5.7 Minimum Spanning Tree C/0 4.5 Mirror Images A/0 1.7 Misa A/1 2.1 Missing Gnomes A/0 3.3 Missing Number A/0 3.4 Missing Numbers A/0 1.7 Mixed-Base Arithmetic A/1 6.7 Mixed Fractions A/1 1.7 Mjehuric B/0 1.7 Moderate Pace A/0 1.6 Modular Arithmetic A/2 3.5 Modulo A/0 1.6 Modulo Data Structures E/2 4.7 Modulo Solitaire C/0 2.7 Molecules A+/2 3.6 Molekule C/0 3.5 Money Matters C/1 3.3 Traveling Monk B+/0 3.3 Let's Play Monopoly! C/0 4.1 Monument Maker A+/0 4.4 Just A Few More Triangles! E/3 6.4 Morse Code Palindromes A/0 3.0 Intergalactic Mortgage A/3 6.1 Moscow Dream A/1 2.7 Mosquito Multiplication A/1 1.8 Mountain Biking A/2 3.1 Movie Collection E/0 4.4 Movie Night C+/2 6.5 Moving Day A/0 2.3 Mravi C/1 2.5 Mravojed A/0 6.2 MrCodeFormatGrader A/0 2.1 Muddy Hike D/0 3.6 Mult! A/1 1.7 Multigram A/0 2.8 (More) Multiplication A/1 2.1 Multiplication Game E/2 5.4 Multiplication Table A/2 2.9 - 3.4 Musical Chairs B+/0 3.5 Musical Notation A/0 2.0 Musical Scales B/0 1.6 Musical Trees A/0 3.4 Music Collection B/0 3.8 Music Your Way B/0 2.3 Muzicari C+/0 5.2 Name Generation A/0 2.3 Palindrome Names A/0 4.0 Name That Permutation B/3 4.4 Narrow Art Gallery C/0 3.1 Nasty Hacks A/0 1.4 Natjecanje C/0 2.2 Natrij A/1 3.1 Necklace Decomposition E/0 4.2 Neighborhood Watch A/2 3.5 Nered A+/1 3.5 Neutral Ground C/0 3.6 Wireless is the New Fiber C/2 3.3 Nicknames B/0 3.5 Nikola C/ 4.1 Nimionese A/0 2.2 I Hate The Number Nine A/2 3.0 Nine Knights A/0 2.1 Nine Packs C/1 4.0 Ninety-nine A/1 1.2 - 3.2 Nizovi B/0 3.3 No Duplicates A/0 1.5 Non-negative Partial Sums A+/0 7.1 Non-Prime Factors A/3 6.0 Noonerized Spumbers B/0 2.7 NOP A/0 2.1 Not Amused B/0 2.5 No Thanks! A/0 1.9 N-Puzzle A/1 2.1 N-sum A/0 1.4 Determining Nucleotide Assortments A+/0 3.7 Number Colosseum B/0 5.2 Number Fun A/2 1.6 Numbers A/3 8.0 Number Sets C/2 4.5 Number Sets (Hard) C/2 7.2 Numbers On a Tree B/1 2.0 Ocean Currents D/0 5.1 Odd A's, Even B's A/3 5.5 Odd and Even Zeroes B/3 6.5 Odd Binomial Coefficients A/3 3.7 Odd Echo A/0 1.3 - 1.4 Odd Gnome A/0 1.8 Oddities A/0 1.4 Odd Man Out B-/0 1.6 Odds of Mia A/2 2.3 Office Space A/0 4.9 Reverse A/0 1.3 - 1.5 Oktalni A/1 1.9 Okvir A/0 2.1 Okviri A/0 2.0 Older Brother A/2 3.2 Olympus Måns A/1 3.9 - 4.8 One Chicken Per Person! A/0 1.9 Ones A/2 4.7 Open-Pit Mining D/0 4.2 Open Source B/0 3.3 First Orchard C/2 3.8 Orderly Class A+/0 3.9 Restaurant Orders C/0 5.3 Ordinary Ordinals A/2 3.6 Organ-free Man A/0 4.9 Origami A/3 5.8 Ornaments A/1 2.5 Östgötska A/0 1.7 Otpor E/1 3.7 Out of Sorts B/0 2.8 Outsourcing E/0 7.8 OvalWatch B/0 3.2 Overdraft A/0 2.0 Overlapping Maps B/3 4.9 Over the Hill, Part 1 A/2 2.5 Over the Hill, Part 2 E/3 6.3 The Owl and the Fox A/2 1.8 Ozljeda C/2 5.8 Pachinko Probability C/2 5.6 Pachyderm Peanut Packing A/1 1.9 Page Layout D/1 5.3 Paintball C/0 3.4 Paint Buckets B+/0 4.7 Paintings B/1 3.9 Pairing Socks B/0 2.7 Palindrome Substring C/0 4.1 Palindromic Password B/0 3.7 Panda Chess D/0 6.1 Parallel Analysis C/0 4.1 Parket A/2 2.4 Parking A/0 2.3 Parking A/0 1.6 Parsing Hex A/1 2.5 Particle Collision A/3 5.7 Party Game B/3 4.2 Pascal A/2 4.1 Password Hacking A/2 2.1 Path Crossings B/0 2.8 Paths D/0 1.3 - 4.3 Path Tracing B/0 3.3 Patuljci B/0 1.8 Paul Eigon A/1 1.7 Pawn Shop B/1 3.5 Pea Pattern A/0 4.4 Pear-wise Voting C/0 4.1 Pea Soup and Pancakes A/0 2.6 Pebble Solitaire C/0 2.3 Pebble Solitaire C/0 2.9 Peg A/0 2.0 Peg Game for Two C+/0 3.2 Peragrams A/0 1.9 Perfect Path Patrol B+/1 6.0 Perfect Pth Powers A/2 5.3 Periodic Strings A/0 2.5 Perket A/0 2.4 Permutation Code A/2 2.4 Permutation Descent Counts A/2 2.0 Permutation Encryption A/1 2.6 Permuted Arithmetic Sequence A/1 2.1 Persistent Numbers A/2 4.1 Pervasive Heart Monitor A/0 1.8 Pet A/0 1.5 Pharmacy B+/0 3.7 Phone List B/0 3.8 Pianino B/1 5.7 Piano Lessons C/0 4.1 Pick up sticks C/0 5.1 Pie B/1 3.7 Piece It Together E/0 6.1 Piece of Cake! A/1 1.5 Pig Latin A/0 2.2 A Vicious Pikeman (Easy) B/1 2.9 Pipe Rotation C/0 3.2 Pitch Performance A/2 5.0 Pivot B/0 2.4 Pizza Delivery A/1 4.6 Pizza Crust A/1 1.7 Pizza Hawaii B/0 2.3 Pizza Party! C/0 6.3 Planetaris A/0 2.5 Planina A/1 1.4 Planting Trees A/0 1.8 Platforme B/0 2.7 Platform Placing A+/1 4.9 Playfair Cipher B/0 2.9 Playground A+/1 5.0 Playing the Slots E/2 3.3 Please, Go First B/0 3.3 Plotting Polynomials A/2 2.4 Mr. Plow King B/3 3.2 Plus Minus A/3 5.0 Point in Polygon A/3 5.9 Pokechat A/0 1.4 Poker Hand B/0 1.4 Polish Notation B/0 3.4 The Uncertainty of Politics C/1 5.4 Polygon Area A/2 3.0 Polynomial Multiplication 1 A/2 2.0 Polynomial Multiplication 2 E/3 6.0 Pop! A/3 3.6 Popkorn A/1 1.4 - 3.3 Poplava A/3 4.3 Popularity Contest A/0 2.0 Immortal Porpoises A/3 2.6 Pot A/1 1.5 Powers and Modulus A/2 5.0 Powers of 2 (Easy) A/0 2.3 Power Strings C/2 6.2 Prefix Free Code B+/3 7.2 Prerequisites? A/0 2.0 Presidential Elections C/2 4.7 Pretty Good Cube Root B/1 5.6 Primal Representation B/2 4.8 Primary Arithmetic A/1 3.0 Prime Count C/3 4.6 - 8.9 Prime Matrix A/3 4.3 Prime Path C/2 2.4 Prime Reduction C/2 3.3 Peculiar primes B/2 6.1 Blackboard Numbers A/2 4.1 Prime Sieve A/2 4.9 Primonimo E/2 6.0 Prince and Princess D/0 6.2 Saving Princess Peach A/0 2.1 Prinova A/2 5.1 Printing Costs A/0 2.2 Pripreme A/1 2.7 Problem Classification B/0 2.9 Product Divisors B/2 6.3 Profitable Pizzas D/0 7.3 Programming Team Selection E/0 6.0 Programming Tutors C/0 4.4 Progressive Scramble A/1 2.1 Promotions D/0 6.3 Proofs B/0 2.4 Prosjek A/2 4.3 Protecting the Collection A+/0 3.8 Provinces and Gold A/0 1.5 Prozor A/0 1.8 Prsteni A/1 1.6 Prva A/0 1.8 Pseudoprime numbers A/2 3.7 Ptice A/0 1.6 Pub-lic Good C/0 3.7 Pulling Their Weight C/0 4.7 Purple Rain D/0 3.7 Putovanje A/0 2.6 Pyramid Construction A/1 4.7 Building Pyramids A/0 1.4 - 1.5 Pyro Tubes A/2 5.2 Quality-Adjusted Life-Year A/0 1.4 Qanat A/3 2.4 Quadrant Selection A/0 1.3 Quadratic Dissonance A/2 2.7 Quadratic Residues A/3 5.4 Verify This, Your Majesty A/1 2.9 The Queen's Super-circular Patio B/2 3.1 Quick Brown Fox B/0 1.8 Quick Estimates A/0 1.6 Quickscope B/0 3.4 Quite a Problem A/0 2.3 R2 A/1 1.4 Race Day B/0 3.8 Racing Around the Alphabet A/1 1.6 Raðir A/0 4.0 White Water Rafting A/3 3.0 Ragged Right A/0 1.9 Raid Teams B/0 3.5 Railroad Map C+/0 7.0 Railroad A/2 1.5 Toy Railway C+/0 6.0 Rainbow Road Race C/1 3.7 Raising the Bar B/3 4.8 A Rank Problem A/0 2.3 Rating Problems A/1 1.4 Restaurant Ratings A/3 3.8 Rational Arithmetic A/1 3.5 Rational Ratio A/2 5.3 A Rational Sequence A/2 5.3 A Rational Sequence 2 A/2 1.6 A Rational Sequence (Take 3) A/1 1.7 RATS B/2 5.8 Razbibriga A/0 5.4 Razgovori A+/0 4.6 Reachable Roads C/0 2.2 Reactivity Series C/0 3.4 Rečenice B/0 3.0 Scaling Recipes A/1 1.8 Reconstructing Tape Art B+/0 4.6 Recount B/0 2.1 Rectangle Area A/0 1.5 The Rectangles Are Surrounding Us! A/0 2.9 Growing Rectangular Spiral A/1 3.0 Recursion + Rand = !Fun B+/1 6.3 Exam Redistribution B/0 2.1 Red Rover A/0 1.9 Reduced ID Numbers B/1 2.4 Work Reduction D/1 5.7 Refrigerator Transport A/1 1.6 - 2.2 Primary Register A/1 2.1 Relatives A/2 3.9 Relocation A/0 1.5 Remainder Reminder A/3 6.0 ReMorse B/3 2.2 Repeated Substrings E/0 6.4 Repeating Decimal A/2 3.6 Repetitive Song A/0 2.2 Research Productivity Index C/3 3.4 Reservoir B+/0 5.1 Reseto A/3 2.4 Working at the Restaurant B/0 4.0 Restaurant Opening A/1 2.0 Retribution! B/1 5.9 Reversed Binary Numbers A/1 1.5 Reverse Rot A/1 1.7 Reversing Roads D/0 4.1 Rhyming Slang B/0 2.8 Ricochet Robots C/0 4.3 Riječi A/1 1.6 Rimski B/0 4.1 Rhyme Power B/0 4.4 Rings C/1 5.6 Rings C/0 3.9 Robotopia A/3 5.4 Robot Protection E/2 2.7 Robots E/0 6.7 Robots on a Grid C/0 4.1 Robot Turtles C+/0 3.7 Rock Band C+/0 4.1 Rock Climbing C/0 5.5 Rock-Paper-Scissors Tournament A/1 4.0 Rock, Scissors, Paper A/0 4.2 Roll Call B/0 2.5 Roman Holidays B/1 5.2 Roaming Romans A/1 1.7 Room Painting A/0 3.5 Rooted Subtrees E/1 4.0 Rot A/0 3.2 Rotate and Cut A/0 3.5 Rounded Buttons A/1 3.7 Round Trips D/2 5.6 Royal Family Tree B/0 4.4 Run-Length Encoding, Run! A/0 1.9 Running MoM C/0 3.8 Running Steps A/2 2.7 Sabor C/0 4.3 Sacred Texts A/0 3.5 Cracking The Safe D/0 3.0 Safe Houses C/0 2.7 Safe Passage D/0 4.7 Sanic A/1 2.5 Santa Klas A/1 2.9 Yet Satisfiability Again! D/2 3.8 Saving Daylight A/1 2.0 Saving For Retirement A/1 2.0 Saving the Universe C/0 4.4 Eb Alto Saxophone Player B/0 2.1 Scaling Recipe A/0 1.9 Mountain Scenes C/2 3.6 School Spirit A/1 1.7 Score! A/0 3.3 Screamers in the Storm A/3 6.3 Hacking the Screen E/1 4.2 Scrolling Sign A/0 3.0 Secret Chamber at Mount Rushmore B/0 2.7 Secret Message A/0 1.8 Secret Santa A/3 3.0 Secret Santa Cycles C+/0 6.6 Secure Doors B/0 1.7 Line Segment Distance A/3 4.2 Select Group B/0 3.8 Self-Similar Strings B+/0 3.2 Selling Spatulas D/0 7.6 Semafori A/1 1.9 Sentry Robots C/0 3.5 Dividing Sequence A/1 4.0 0-1 Sequences C/2 6.7 Sequential Manufacturing A/0 2.9 Server A/0 1.7 Set! A/2 2.0 SETI A/3 3.2 Setnja B+/2 4.8 The SetStack Computer B+/2 6.2 Settlers of Catan B/3 4.2 Seven Wonders A/1 1.5 SG Coin A+/2 2.6 Shattered Cake A/1 1.4 Sheldon Numbers A/3 5.0 Shiritori A/0 2.4 Shopaholic A/0 2.3 Shopping D/0 5.5 Shopping List B/0 3.3 Shopping List (Easy) B/0 2.0 Shopping Malls C/1 4.1 Divisibility Shortcut A/2 4.1 Shortest Composite Sum A/1 4.8 Single source shortest path, non-negative weights C/0 3.6 Single source shortest path, time table D/1 3.9 Single source shortest path, negative weights D/0 4.8 Shortlex A/2 5.0 Short Sell A+/0 4.2 Elegant Showroom C/0 4.2 Shuffling Along B/0 2.5 Sibice A/1 1.5 Sideways Sorting A/0 2.3 Digit Product A/0 1.6 Bridging Signals E/0 3.8 Sign Profile A/2 5.7 Silver Star Stands Alone C/0 3.4 Sim B/0 3.7 Simon Says A/0 3.1 Simone B/0 2.0 Simon Says A/0 1.6 Simple Addition A/0 2.2 Simple Arithmetic A/1 1.2 - 5.0 Simple Cron Spec B/1 2.0 Simple Solitaire A/0 5.3 Simplicity B/0 2.9 Simply Sudoku B+/0 3.6 Sjecista A/2 1.9 Skener A/0 1.6 Ski Jumping B/2 3.0 Ski Lifts B/0 3.9 Skocimis A/1 1.6 Graduation B/0 1.2 - 2.2 Going to School C/0 3.3 - 3.4 Skru op! A/0 1.4 - 1.6 Sky Islands C/0 2.1 Slalom 2 B/2 6.1 Slatkisi A/1 2.0 Slicice C/0 6.1 Slide Count B/0 4.0 Sliding Tiles B+/0 4.5 Slikar C/0 3.4 Slom A/3 4.7 Slow Leak C/0 5.7 Smallest Calculated Value A/1 3.2 Smallest Multiple A/2 3.3 Small Schedule A/2 3.2 Smart Phone A/0 2.6 SMIL A/0 1.4 - 1.5 Smoothie Stand A/1 2.7 Snakes and Masters A/2 3.3 Snapper Chain (Easy) A/2 2.7 Snapper Chain (Hard) A/2 2.4 S-Nim B/3 3.6 Unique Snowflakes B/0 4.1 Social Advertising D/0 4.4 Social Distancing A/0 2.2 Social running A/0 2.2 Soda Slurper A/1 1.8 Soft Passwords A/0 2.5 Sok A/1 1.7 Peg Solitaire C/0 3.2 Some Sum A/1 2.3 Sort B/0 2.5 Sort of Sorting A/0 1.8 Sort Two Numbers A/0 1.4 The Sound of Silence B+/0 4.6 Soundex A/0 2.6 Soylent A/1 1.7 Space Mail C/1 4.7 Sparkle's Seven C/0 6.1 Spavanac A/1 1.4 Speaking of Which A/2 7.8 Need for Speed B/2 3.4 Speeding A/1 1.6 Speed Limit A/1 1.5 Speedrun B/0 2.2 Sperhling A/0 2.3 Spelling Bee A/0 2.0 Spiderman's Workout C/0 4.5 Prime Spiral C+/0 3.3 Splat A/1 2.5 Square Deal A/1 4.0 Square Fields (Easy) B/2 5.8 Square Peg A/1 1.7 Square Peg in a Round Hole B/1 3.0 Squawk Virus C/3 3.4 Srednji A/2 4.0 Sretan A/2 2.9 Stacking Up B/1 5.9 Stamp Combinations C/0 5.2 Biased Standings B/1 3.8 Star Arrangements A/1 1.7 Star Battles I A/0 2.9 A Star not a Tree? E/3 7.0 Star Wars Movies B+/0 6.7 Statistics A/0 1.9 Sticky Situation A/1 2.7 Stigavörður E/1 5.5 Stikl E/0 5.7 Stirling's Approximation A/3 4.7 Daydreaming Stockbroker A/1 3.3 Stock Prices B/0 4.1 Stogovi E/0 8.1 Stol E/0 6.2 Stopwatch A/1 1.4 Straights A/0 3.5 Stream Lag A/0 3.2 Streets Ahead A/0 1.9 String Factoring C/0 5.0 String Matching E/0 4.5 Structural Differences E/0 7.4 Subcommittees A/3 5.8 Counting Subsequences (Hard) C/0 3.7 Subsequences in Substrings C/0 5.0 The Power of Substitution B/3 7.5 Repeated Substrings E/0 6.3 Subway Tree System B+/0 4.7 Subway C/1 5.2 Subway Map E/0 7.9 Subway Planning C/2 2.0 Successful Zoom A/0 2.2 Succession C/0 3.0 Suffix Array Re-construction C/0 4.2 Suffix Sorting E/0 6.2 Sum Kind of Problem A/1 1.8 Summer Trip C/0 2.9 Sum of the Others A/0 2.3 Sum Squared Digits Function A/1 1.5 Sun and Moon A/1 1.7 Supercomputer E/0 2.8 Surveillance Squared A/3 7.3 Suspension Bridges B/1 2.9 Svada B+/1 3.9 Support Vector Machine A/1 4.3 Swapping Places C+/0 6.7 Swap to Sort C/0 3.9 Sylvester Construction B/1 2.2 Symmetric Order B/0 1.6 Synchronizing Lists B/0 1.6 T9 Spelling B/0 1.7 Tabs and spaces A/0 3.5 Tai's formula A/2 1.6 Tajna A/1 2.1 Aquarium Tank B/2 5.0 Target Practice A/3 6.9 Tarifa A/1 1.5 Tautology B/2 3.1 Teacher Evaluation A/2 3.0 Happy Telephones C/0 3.0 Time Travelling Temperatures A/2 2.1 Temperature Confusion A/1 2.6 Tenis A/0 4.2 Tenkici B/2 6.1 Teque B/0 2.9 Ternarian Weights B/2 3.8 Terrace Hill B/0 5.4 Terraces C/0 3.7 Test Drive A/0 1.9 Tetration B/1 1.6 Tetris A/0 1.7 Texas Summers D/1 4.3 Text Encryption A/0 3.3 Text Messaging Outrage A/0 2.9 Texture Analysis A/0 3.0 Thank God it’s Friday A/0 3.1 Thanos A/1 2.4 Thanos the Hero A/0 3.6 That's One Hanoi-ed Teacher B/0 4.9 The Backslash Problem A/0 2.3 The Big Mac Question C+/0 8.2 The Colonization of El-gă-rizm C/0 5.7 The Deal of the Day B/2 2.1 The Grand Adventure B/0 2.1 The King of the North C+/0 4.8 The Last Problem A/0 1.6 The Plank B/0 1.7 - 1.8 Thermostat Trouble A/2 3.8 Thesaurus C/0 5.0 I'm Thinking of a Number A/2 3.7 This Ain't Your Grandpa's Checkerboard A+/0 1.7 Thore's self-esteem A/0 4.5 Three Dice B/0 5.6 Three Powers A/2 2.2 Game of Throwns B/0 2.6 Plane Ticket Pricing C/0 4.4 Tic-Tac State A/1 2.5 Tic Tac Toe C/1 5.2 Tic Tac Toe Counting B/0 3.4 Tide Goes In, Tide Goes Out D/1 5.1 Tight words C/2 3.3 Tight-Fit Sudoku E/0 4.5 Tildes C/0 2.7 Timebomb A/0 1.8 Stuck In A Time Loop A/0 1.4 Time Zones A/1 4.2 Timing B/3 4.0 Tired Terry A/0 3.4 Toast A/2 4.9 Töflur A/1 2.4 Toilet Seat A/0 2.3 ToLower A/0 2.3 Tom and Jerry C/3 6.8 Tomography C/0 4.2 TomTom Cruise D/0 6.4 Torn To Pieces C/0 3.1 Tower Construction A/0 1.7 Touchdown! A/0 4.5 Touchscreen Keyboard B/1 2.3 Tour de France B/1 2.9 Tourists E/1 4.1 A Towering Problem B/0 2.3 Toys A/3 4.2 Track Smoothing A/2 1.8 Train Boarding B/0 3.7 Train Passengers A+/0 2.8 Train Sorting E/0 6.4 Tram A/2 2.1 Transit Woes A/2 1.5 Transportation Planning C/0 4.2 Travel the Skies B/0 3.5 Treasure Diving D+/0 6.6 Treasure Hunt B/0 2.6 Treasure Map A/3 5.4 Treehouses C/0 3.6 Treequivalence E/0 8.9 Tree Shopping B+/0 3.5 Trending Topic B/0 5.0 Tri B/0 1.7 Sierpiński Circumference A/3 2.9 Triangle Drama A/0 3.1 Triangle Ornaments A/3 2.1 Triangular Collection A/2 6.1 Triangle Area A/0 1.4 Trick or Treat B/2 3.6 Trik A/0 1.5 Triangle Trilemma A/2 3.3 The Trip, 2007 B/0 2.9 Triple Texting A/0 1.7 Trip Odometer B/0 2.2 Trip Planning A/0 3.0 Tri Tiling C/1 2.6 Trojke B/2 3.4 Troll Hunt A/1 2.3 Travelling Salesperson 2D E/0 1.5 - 9.5 Tunnelling the Earth A/3 3.3 Turbo E/0 4.4 Turning Trominos B/3 4.9 Turtle Master B/1 2.8 ICPC Tutorial A/2 3.4 Take Two Stones A/1 1.3 Two-sum A/0 1.4 Ultimate Binary Watch A/0 1.6 Ultra-QuickSort C/0 5.1 Umm Code B/1 3.5 UnDetected C/0 3.6 (un)Fair Play D/0 5.1 Union-Find C/0 4.4 Units C/1 3.3 University Zoning B/0 2.7 Unlock Pattern A/1 1.7 Unlock Pattern II A/3 7.3 Unread Messages B/0 4.2 Arrangement A/1 1.2 - 1.5 The Ups and Downs of Investing A+/0 3.6 Urban Design A/3 4.2 Using Digits C/0 4.7 UTF-8 A/0 2.0 The Uxuhul Voting System C/1 3.3 Vaccine Efficacy A/1 2.6 Vacuumba A/1 1.8 Right-of-Way A/0 2.1 Vanishing Parentheses C/0 5.1 Variable Names B/0 4.8 Variable Arithmetic B/0 2.5 Varied Amusements C/0 2.3 - 3.8 Vauvau A/1 1.9 Veci A/1 1.9 Boiling Vegetables B+/0 3.4 Victory Through Synergy E/0 3.3 Video Speedup A/1 1.8 Virtual Friends C/0 4.5 Virus Replication A+/0 3.5 VisuAlgo Online Quiz D/0 3.6 VivoParc E/0 5.2 Volim A/1 1.7 Volume Amplification B+/0 7.2 Popular Vote B/0 2.0 Vudu C/1 4.4 Vuk D/0 3.6 Waif Until Dark C/0 2.9 A Walk Through The Forest C/0 5.0 Trapezoid Walkway C/2 3.5 Lifting Walls B/1 4.3 Walrus Weights C+/0 3.4 Warehouse B/0 2.1 War on Weather A/3 3.6 Warring Scoring A/0 3.3 Watchdog A/1 2.2 Water D/0 3.6 Watersheds C/0 3.6 Weak Vertices A/0 1.6 The Weight Of Words A/1 2.6 Weighty Tomes D/0 4.5 Welcome to Code Jam (Easy) A/0 2.1 Welcome to Code Jam (Hard) C/0 4.3 WERTYU B/0 3.3 Wet Tiles C/0 4.1 WFF 'N PROOF A+/0 3.0 What does the fox say? B/0 2.3 Wheels C/2 3.4 Where's My Internet?? C/0 2.9 Where to Live? A/1 4.0 Which Base is it Anyway? A/2 2.6 Which is Greater? A/0 1.4 The White Rabbit Pocket Watch E/1 4.0 Who's the Boss? C/0 6.2 Wimbledon A/2 4.8 Win Diesel D/0 4.8 Wizard of Odds A/1 2.6 Wonky Pizza B/2 4.4 Wood Cutting C-/0 2.7 Wooden Signs C+/0 3.3 Word Cloud A+/0 2.4 Word Equations B+/0 7.7 Words for Numbers A/0 2.9 WordSpin C/0 5.9 Workers of the World Unite! Just Not Too Close. E/0 4.5 Working From Home A/0 4.4 Workout for a Dumbbell B+/0 5.4 Assigning Workstations B/0 2.6 Worst Weather Ever E/0 7.7 Board Wrapping E/2 3.7 XOR Equation A+/2 4.9 Yin and Yang Stones A/1 1.7 Yoda A/0 2.1 You Be the Judge! A/1 5.7 You be The Judge, Again B/0 3.7 Yule Lads B/3 2.1 - 7.5 Zadaca A/1 4.2 Zagrade B/0 3.3 Zamka A/0 1.5 Stand on Zanzibar A/1 1.5 Zapis C+/1 5.2 Zbrka A/3 5.6 Zebras and Ocelots A/1 2.9 Zig Zag Nametag A/1 4.0 Zigzag A/0 5.0 Zipf's Law B/0 5.9 Zipf's Song B/2 4.4 Zipline A/3 3.3 Znanstvenik B+/0 3.8 Zoning C/0 5.2 Zoning Houses E/1 6.9 Un-bear-able Zoo A/0 1.9 Zoom A/0 1.7 Zyxab B/0 3.0

FAQs
Kattis has over 2500 problems from many competitions and training sessions, so where to start and how to progress?

What does it mean kattis solution? ›
Kattis is a website that allows students to submit solutions to programming problems, and have them evaluated automatically by running a series of test cases on the submitted solutions . You will be able to test your solution to the programming assignments on Kattis.

Why is my kattis score not updating? ›
Scores are only updated every few minutes — your score and rank will not increase instantaneously after you have solved a problem, you have to wait a short while .

What is the compilation error in kattis? ›
Giving an incorrect, or not public, main class for a java program will cause a compile error ! Compile times over 1 minute will cause a compile error. A compile error does not give you any penalty time. Judge Error means that you've found a bug (or at least misconfiguration) in the judge.

How to test code in Kattis? ›
Testing your solution before submitting to Kattis Press Enter, and then Control-D . This will make the problem run with the provided input, and it will print out an answer. If the answer matches the sample output provided in the Kattis problem statement, it means your solution works for that input.

How do you submit to kattis? ›
If you are logged in, you have a link Submit to a submit form that you can use to upload code . The form supports submitting multiple files, to do this you simply select all the files you want to submit in the file chooser dialog.

What is runtime error in kattis? ›
Run Time Error means your program crashed during execution with our secret test input . More precisely it means that it terminated with a non-zero exit code, or with an uncaught exception.

How to submit problems in Kattis? ›
If you are logged in, you have a link Submit to a submit form that you can use to upload code . The form supports submitting multiple files, to do this you simply select all the files you want to submit in the file chooser dialog.

How many problems are there in Krotov? ›
The book contains 250 problems and their solutions. These problems were meant for the Moscow physics olympiad. The problems are divided into four sections - mechanics, heat and molecular physics, electricity and magnetism, and optics.

Are there problems that algorithms can't solve? ›
There are two categories of problems that an algorithm cannot solve. Undecidable Problems . These problems are the theoretically impossible to solve — by any algorithm. The halting problem is a decision problem (with a yes or no answer) that is undecidable.

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