| #19401 | Mysterious VillaCTU Open Contest 2002 | |
| #19402 | Too Much WaterCTU Open Contest 2002 | |
| #19403 | Bridge HandsCTU Open Contest 2003 | |
| #19404 | Charlie's ChangeCTU Open Contest 2003 | |
| #19405 | Building a New DepotCTU Open Contest 2003 | |
| #19406 | Truck HistoryCTU Open Contest 2003 | |
| #19407 | Base NumbersCTU Open Contest 2003 | |
| #19408 | Paper CuttingCTU Open Contest 2003 | |
| #19409 | Hexagonal RoutesCTU Open Contest 2003 | |
| #19410 | StorehouseCTU Open Contest 2003 | |
| #19411 | Traffic JamCTU Open Contest 2003 | |
| #19412 | AgentsCTU Open Contest 2004 | |
| #19413 | BoatherdsCTU Open Contest 2004 | |
| #19414 | C LooooopsCTU Open Contest 2004 | |
| #19415 | Death to Binary?CTU Open Contest 2004 | |
| #19416 | ElectricityCTU Open Contest 2004 | |
| #19417 | FirepersonsCTU Open Contest 2004 | |
| #19418 | God of the Vile BaskersCTU Open Contest 2004 | |
| #19419 | HerbalistsCTU Open Contest 2004 | |
| #19420 | Inglish-Number TranslatorCTU Open Contest 2004 | |
| #19421 | Japan Plotter DriverCTU Open Contest 2004 | |
| #19422 | All FriendsCTU Open Contest 2005 | |
| #19423 | Board GameCTU Open Contest 2005 | |
| #19424 | CraneCTU Open Contest 2005 | |
| #19425 | DivisorsCTU Open Contest 2005 | |
| #19426 | Emag eht htiw Em PlehCTU Open Contest 2005 | |
| #19427 | Failing RoadsCTU Open Contest 2005 | |
| #19428 | Go EndgameCTU Open Contest 2005 | |
| #19429 | Help Me with the GameCTU Open Contest 2005 | |
| #19430 | IVXLCDMCTU Open Contest 2005 | |
| #19431 | Tree Marking AnimalsCTU Open Contest 2006 | |
| #19432 | Black BoxesCTU Open Contest 2006 | |
| #19433 | Chocolate EatingCTU Open Contest 2006 | |
| #19434 | srebmuN desreveR gniddACTU Open Contest 2006 | |
| #19435 | Extra SafetyCTU Open Contest 2006 | |
| #19436 | Numbers FactorizationCTU Open Contest 2006 | |
| #19437 | Random GeneratorsCTU Open Contest 2006 | |
| #19438 | Ball Lightning -- Help with the MovingCTU Open Contest 2006 | |
| #19439 | IntercalCTU Open Contest 2006 | |
| #19440 | Catch the Bus!CTU Open Contest 2007 | |
| #19441 | Calendar of EventsCTU Open Contest 2007 | |
| #19442 | Roman ExpressionsCTU Open Contest 2007 | |
| #19443 | Geometric ShapesCTU Open Contest 2007 | |
| #19444 | Corporate IdentityCTU Open Contest 2007 | |
| #19445 | Money Money Money, Must Be FunnyCTU Open Contest 2007 | |
| #19446 | Railway TransportationCTU Open Contest 2007 | |
| #19447 | Soccer TournamentCTU Open Contest 2007 | |
| #19448 | HypertheseusCTU Open Contest 2007 | |
| #19449 | Alea iacta estCTU Open Contest 2008 | |
| #19450 | On-Line BankingCTU Open Contest 2008 | |
| #19451 | International Collegiate Programming ContestCTU Open Contest 2008 | |
| #19452 | Careful DeclarationCTU Open Contest 2008 | |
| #19453 | Stock ExchangeCTU Open Contest 2008 | |
| #19454 | Wooden FenceCTU Open Contest 2008 | |
| #19455 | Safe GamblingCTU Open Contest 2008 | |
| #19456 | Government HelpCTU Open Contest 2008 | |
| #19457 | Tree InsertionsCTU Open Contest 2008 | |
| #19458 | Arable AreaCTU Open Contest 2009 | |
| #19459 | Clock CaptchaCTU Open Contest 2009 | |
| #19460 | Digital DisplayCTU Open Contest 2009 | |
| #19461 | Intriguing IdentifiersCTU Open Contest 2009 | |
| #19462 | Letters LiesCTU Open Contest 2009 | |
| #19463 | Odd OpportunitiesCTU Open Contest 2009 | |
| #19464 | Peculiar PrimesCTU Open Contest 2009 | |
| #19465 | Robotic RailsCTU Open Contest 2009 | |
| #19466 | Suspicious StocksCTU Open Contest 2009 | |
| #19467 | Arbitrage?CTU Open Contest 2010 | |
| #19468 | Bus SchedulesCTU Open Contest 2010 | |
| #19469 | Bus Clock DisplayCTU Open Contest 2010 | |
| #19470 | Measuring Problem DifficultyCTU Open Contest 2010 | |
| #19471 | The Easiest Problem is This OneCTU Open Contest 2010 | |
| #19472 | Prohibición de fumarCTU Open Contest 2010 | |
| #19473 | Pyramid GuardsCTU Open Contest 2010 | |
| #19474 | Hack around the LockCTU Open Contest 2010 | |
| #19475 | God Save the i-th QueenCTU Open Contest 2010 | |
| #19476 | Analog Clock DisplayCTU Open Contest 2011 | |
| #19477 | Collatz ConjectureCTU Open Contest 2011 | |
| #19478 | Text EncryptionCTU Open Contest 2011 | |
| #19479 | Mine the GradientCTU Open Contest 2011 | |
| #19480 | InvasionCTU Open Contest 2011 | |
| #19481 | Intergalactic MortgageCTU Open Contest 2011 | |
| #19482 | Simple PolygonCTU Open Contest 2011 | |
| #19483 | Ambiguous ResultCTU Open Contest 2011 | |
| #19484 | Domino tilingCTU Open Contest 2011 | |
| #19485 | Andrew the AntCTU Open Contest 2012 | |
| #19486 | Software BugsCTU Open Contest 2012 | |
| #19487 | Charlie the CockchaferCTU Open Contest 2012 | |
| #19488 | Gregory the GrasshopperCTU Open Contest 2012 | |
| #19489 | Lisa the LadybugCTU Open Contest 2012 | |
| #19490 | Mosquito MultiplicationCTU Open Contest 2012 | |
| #19491 | Rhinoceros BeetleCTU Open Contest 2012 | |
| #19492 | Simon the SpiderCTU Open Contest 2012 | |
| #19493 | Fractional LotionCTU Open Contest 2013 | |
| #19494 | Folded MapCTU Open Contest 2013 | |
| #19495 | Furry NuisanceCTU Open Contest 2013 | |
| #19496 | Fence OrthogonalityCTU Open Contest 2013 | |
| #19497 | Flower PotsCTU Open Contest 2013 | |
| #19498 | Frustrated QueueCTU Open Contest 2013 | |
| #19499 | Frozen Rose-HeadsCTU Open Contest 2013 | |
| #19500 | False Sense of SecurityCTU Open Contest 2013 | |