Changes in task difficulty level - July 2023

Codility has processes in place for evaluating how candidates score at each task to be sure their difficulty level fits into the right category, so when we notice that average candidate scores are not reflective of the estimated difficulty level, we make adjustments.

Each task we release we analyze further based on how candidates score at it. If we see that, for example, candidates fail too often on a task marked as easy, we change its difficulty to medium once we have enough data. You can see the thresholds we apply here.

On July 5, 2023, we're adjusting the difficulty level of 73 fundamental tasks and 126 real-life tasks. You can see the full list below.

Fundamental tasks

AngleBrackets to hard
BalancedRectangles to medium
BankTransfers to easy
BattleshipRecognition to easy
BinaryPositiveAnd to easy
BugfixingMaxNonnegSliceSum to medium
BugfixingPythonMinDiff to medium
ConsecutiveElementsDifferences to elementary
ContactDialer to elementary
CorrespondingFragments to easy
DecreasePollution to hard
DiceRolls to easy
DifferentLettersConcatenation to easy
DistinctNumbersCount to easy
DivisionGame to elementary
EndsTheSame to medium
EraseAdjacentLetters to medium
FairSplits to medium
FileListVarOpal to easy
FinancialPlan to hard
FindRepeatingLetter to elementary
FixTheTable to easy
ForbiddenTrios to easy
FourDigitsPath to medium
GeneratePalindrome to medium
GraphDisappearance to medium
IncreaseMultipliers to hard
InvestmentFocus to elementary
KeySequence to elementary
LargestPalindrome to medium
LargestSumOfWeights to easy
MaxBiValuedSlice to medium
MaxSwitchingSlice to easy
MinStackHeightSum to medium
MoveDisks to elementary
NextSameDigitsSum to easy
ObjectsRendering to medium
OnesInArithSeq to medium
OptimizingFarthestDifferent to medium
PassTheMessage to elementary
PutThreeTiles to hard
Recipes to easy
RedSegment to medium
RemoveFive to easy
ReverseEdges to medium
SameCorners to hard
SanatoriumAccommodation to easy
Seq23 to easy
SpeedMeasurementPoints to elementary
SqlAverageSalary to elementary
SqlCarRace to elementary
SqlCheapestFlats to easy
SqlCurrency to elementary
SqlFilterApplicants to elementary
SqlInjection to hard
SqlLogs to elementary
SqlLogsPortuguese to elementary
SqlPhonecalls to easy
SqlRecommendations to easy
SqlTournament to medium
StonesOnBoard to medium
StringMisspellingVarBeryl to medium
StringMisspellingVarJade to medium
SubmatrixSum to medium
SubtreeInside to easy
TheWidestPath to elementary
Times17DecDigitsSum to medium
TransformString to medium
VaryingPathInTree to medium
XYSplit to easy
XoGame to easy
XorProduct to medium
ZerolessDecomposition to easy

Real-life tasks

AndroidViewmodel to easy
AngularBasket to hard
Angular Counter to elementary
AngularForm to medium
AngularRatings to hard
AngularSideMenu to hard
AnsibleEncryptData to hard
AnsibleRemoteServer to hard
AsyncJobsScheduler to hard
AsynchronousTaskRunner to hard
AuthenticationToken to medium
AzureEventPublisher to hard
BasicApiTests to medium
BlindSqlInjection to hard
BlocStateManagement to hard
BruteForcePassword to medium
CachingDataStructure to hard
CachingDecorators to easy
ChangeDirectory to easy
CheckIndependence to easy
ChefSetupCiServer to hard
ClusteringData to medium
ClusteringForImageSegmentation to medium
CommandHandler to easy
ComplexMakefile to hard
ConfigureDataImport to hard
ConnectionManager to medium
CountryCapitalAngular to hard
CspHeader to medium
CssDropDownMenu to easy
CustomCollection to easy
DateGeneratorJavascript to easy
Django Book Counter to easy
DocumentProcessor to easy
DotnetPagination to hard
EchoServer to medium
ElasticsearchSongs to easy
EvaluateDecisionTree to hard
ExplanatoryAnalysis to easy
ExternalServicesRequests to hard
FieldTranslator to hard
FileUpload to medium
FinancialClustering to hard
FoodBasket to easy
GitlabciAutomaticDeployment to hard
GitlabciBuildAndRelease to hard
HeaderSecurity to hard
HelmCronJob to hard
HibernateCrud to hard
Html5SimpleArticle to medium
InsecureDeserialization to hard
InterceptedForm to hard
Iterable to medium
Java8ReportAggregator to medium
Java8SamplePreprocessing to hard
JsonSchemaValidation to hard
KafkaPartitions to medium
KerasImageClassification to easy
KnnDistance to elementary
KubernetesFixDeployment to easy
LaravelMoviesValidation to elementary
LinearRegression to medium
ListAndMap to medium
LodashArrays to easy
LodashThrottle to easy
MarkowitzStockPortfolio to medium
ModelValidation to hard
MongodbLoginAttempts to hard
MultithreadedGame to hard
MysqlAccessReport to hard
MysqlAccessRoles to hard
NodejsSequelize to easy
OpenApiDefinition to easy
OptimisticConcurrency to hard
PasswordGenerator to elementary
PasswordValidator to medium
PlusOperator to elementary
PocoConfiguration to hard
PodDeployment to easy
PodWebserver to easy
PortScanner to medium
PowershellCountOccurrences to hard
PowershellDiskCleanup to hard
PythonSearchByTag to easy
Python Selenium Login Page to medium
PuppeteerQaAddUserForm to hard
QaCsharpLoginPage to medium
QA Java Search to medium
PuppeteerQaUsersList to hard
ReactLikeDislikeTypescript to elementary
ReactNativeLoginPage to elementary
ReactTypescriptSideMenu to easy
RedisCaching to hard
RxjavaChaining to hard
RxjsSocialApp to hard
SeleniumQaAddUserForm to hard
SeleniumQaUsersList to hard
ServiceClusterip to elementary
SimpleWebsite to hard
SpringAop to hard
SpringCaching to easy
SpringHealthcheck to easy
SpringHibernatePets to medium
SpringTodoList to medium
SqlInjection to hard
SqlalchemyOrm to hard
StoreApi to medium
StrategyPattern to easy
TalentFinder to easy
TensorflowCustomLossFunction to elementary
TerraformSshKeys to hard
TextAnonymisation to easy
TimeSeriesModelsComparison to hard
TimeTracker to medium
UrlrequestProvider to easy
UsersList to easy
VarianceAnalysis to hard
VinLookup to easy
Vue15Puzzle to hard
VueCounter to elementary
VuePagination to easy
VueSideMenu to easy
WorkerPool to hard
XmlEditor to medium
XmlSerialization to hard
XssSecurity to hard