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Solve problems.
Spend at least ~20-60 minutes thinking about a problem before giving up.
Reflect on why you were able/unable to solve each problem.
Marked solved with green.

If possible, simulate actual contest conditions with a 4 hour timer (5 for US Open).

It is not recommended that you solve all the problems in a division. Just
solve enough until you are confident in promotion.		SolvedLogging InMade by Eric Zhang
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Solving
You need to make an account first.
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http://usaco.org/index.php
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Solutions
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Click "Return to Problem List" and then "Solution" for the problem.
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DivisionYearDecemberJanuaryFebruaryMarch (US Open)
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2022-2023BreakdownMaking FriendsPalindromesTractor PathsMana CollectionSubtree ActivationHungry CowProblem SettingWatching CowflixPareidoliaGood BitstringsTriples of Cows
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2021-2022TicketsPaired UpHILOMinimizing HaybalesCounting HaybalesMultiple Choice TestPaitn by RectanglesSleeping in ClassPhone Numbers262144 RevisitedHoof and BrainUp Down Subsequence
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2020-2021CowmistrySpaceshipSleeping CowsSum of DistancesMinimum Cost PathsPaint by LettersNo Time to DryMinimizing EdgesCounting GraphsUnited Cows of Farmer John Routing SchemesBalanced Subsets
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2019-2020Greedy Pie EatersBessie's Snow CowTree DepthCave PaintingsNon-Decreasing SubsequencesFalling PortalsDelegationEquilateral TrianglesHelp YourselfSprinklers 2: Return of the AlfalfaExerciseCircus
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2018-2019Balance BeamSort It OutThe Cow GatheringRedistrictingExercise RouteTrain Tracking 2Cow DatingMoorio KartMowing MischiefTree BoxesCompound EscapeValleys
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Platinum2017-2018Standing Out from the HerdPush a BoxGreedy Gift TakersLifeguardsCow at LargeSprinklersSlingshotNew BarnsCow GymnastsOut of SortsTrain TrackingDisruption
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2016-2017Lots of TrianglesTeam BuildingRobotic Cow HerdPromotion CountingBuilding a Tall BarnSubsequence ReversalWhy Did the Cow Cross the RoadWhy Did the Cow Cross the Road IIWhy Did the Cow Cross the Road IIIModern ArtSwitch GrassCow Basic
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2015-2016Max FlowHigh Card Low Card (Platinum)Counting HaybalesFort MooMowing the FieldLights OutLoad BalancingFenced InCircular Barn262144Bull in a China ShopLandscaping
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2022-2023Bribing FriendsMountainsStrongest Friendship GroupFind and ReplaceLights OffMoo RouteEqual Sum SubarraysFertilizing PasturesPiling PapersCustodial CleanupPareidoliaTree Merging
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2021-2022Paired UpHILOBracelet CrossingsDroughtFarm UpdatesTests for HaybalesRedistributing GiftsCow CampMoo NetworkApple CatchingPair ProgrammingBalancing a Tree
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2020-2021Square PastureBovine GeneticsReplicationUddered but not HerdTelephoneDance MoovesStone GamesModern Art 3Count the CowsUnited Cows of Farmer JohnPortalsPermutation
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2019-2020Milk PumpingMilk VisitsMoortal CowmbatTime is MooneyFarmer John Solves 3SUMSpringboardsTimelineHelp YourselfDelegationHaircutFavorite ColorsExercise
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Gold2018-2019Fine DiningCowpatibilityTeamworkCow PoetrySleepy Cow SortingShortcutCow LandDishwashingPainting the BarnSnakesI Would Walk 500 MilesBalancing Inversions
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2017-2018A Pie for a PieBarn PaintingHaybale FeastMooTubeCow at LargeStamp PaintingSnow BootsDirectory TraversalTaming the HerdOut of SortsMilking OrderTalent Show
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2016-2017MoocastCow ChecklistLasers and MirrorsBalanced PhotoHoof, Paper, ScissorsCow NavigationWhy Did the Cow Cross the RoadWhy Did the Cow Cross the Road IIWhy Did the Cow Cross the Road IIIBovine GenomicsModern Art 2
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2015-2016High Card Low Card (Gold)Fruit FeastBessie's DreamAngry CowsRadio ContactLights OutCircular BarnCircular Barn RevisitedFenced InSplitting the FieldClosing the Farm248
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2022-2023Barn TreeCircular Barn Range ReconstructionLeadersAir Cownditioning IIMoo OperationsBakeryCow-libiMoo Route IIMilk SumFIeld DayPareidolia
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2021-2022Closest Cow WinsConnecting Two BarnsConvulted Intervals
Searching for Soulmates
Cow FrisbeeCereal 2Redistributing GiftsRobot InstructionsEmail FilingVisitsSubset EqualityCOW Operations
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2020-2021CowntagionRectangular PastureStuck in a RutDance MoovesNo Time to PaintSpaced OutComfortable CowsYear of the CowJust Green EnoughMaze Tac Toe
Do You Know Your ABCs?
Acowdemia
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2019-2020MooBuzzMeetingsMilk VisitsBerry PickingLoan RepaymentWormhole SortSwapity Swapity SwapTrianglesClock TreeSocial DistancingCerealThe Moo Particle
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Silver2018-2019ConventionConvention IIMooyo MooyoGrass PlantingIcy PerimeterMountain ViewSleepy Cow HerdingPainting the BarnThe Great RevegetationLeft OutCow Steeplechase IIFence Planning
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2017-2018My Cow Ate My HomeworkMilk MeasurementThe Bovine ShuffleLifeguardsRental ServiceMooTubeRest StopsSnow BootsTeleportationOut of SortsLemonade LineMultiplayer Moo
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2016-2017Counting HaybalesCities and StatesMoocastCow Dance ShowHoof, Paper, ScissorsSecret Cow CodeWhy Did the Cow Cross the RoadWhy Did the Cow Cross the Road IIWhy Did the Cow Cross the Road IIIPaired UpBovine GenomicsWhere's Bessie?
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2015-2016Switching on the LightsHigh Card WinsBreed CountingAngry CowsSubsequences Summing to SevensBuild GatesCircular BarnLoad BalancingMilk PailsField ReductionDiamond CollectorClosing the Farm
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2022-2023Cow CollegeFeeding the CowsReverse EngineeringLeadersAir Cownditioning IIMoo OperationsHungry CowStamp GridWatching MoolooFEBMoo LanguageRotate and Shift
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2021-2022Lonely PhotoAir CownditioningWalking HomeHerdleNon-Transitive DiceDroughtSleeping in ClassPhotoshoot 2BlocksPhotoshootCounting LiarsAlchemy
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2020-2021Do You Know Your ABCs?Daisy ChainsStuck in a RutUddered but not HerdEven More Odd PhotosJust StallingYear of the CowComfortable CowsClockwise FenceAcowdemia IAcowdemia IIAcowdemia III
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2019-2020Cow GymnasticsWhere Am I?Livestock LineupWord ProcessorPhotoshootRaceTrianglesMad ScientistSwapity SwapSocial Distancing ISocial Distancing IICowntact Tracing
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Bronze2018-2019Mixing MilkThe Bucket ListBack and ForthShell GameSleepy Cow SortingGuess the AnimalSleepy Cow HerdingThe Great RevegetationMeasuring TrafficBucket BrigadeMilk FactoryCow Evolution
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2017-2018Blocked BillboardThe Bovine ShuffleMilk MeasurementBlocked Billboard IILifeguardsOut of PlaceTeleportationHoofballTaming the HerdTeam Tic Tac ToeMilking OrderFamily Tree
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2016-2017Square PastureBlock GameThe Cow-SignalDon't Be Last!Hoof, Paper, ScissorsCow TippingWhy Did the Cow Cross the RoadWhy Did the Cow Cross the Road IIWhy Did the Cow Cross the Road IIIThe Lost CowBovine GenomicsModern Art
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2015-2016Fence PaintingSpeeding TicketContaminated MilkPromotion CountingAngry CowsMowing the FieldMilk PailsCircular BarnLoad BalancingDiamond CollectorBull in a China ShopField Reduction
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