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Codility-style coding test prep

Codility practice for correctness and performance.

Work through public-catalog problems with explicit Codility evidence. Use constraints to plan the algorithm, then validate both behavior and scalability.

20-problem previewCodility evidenceEdge cases + complexity
Codility problem preview
52 problems with explicit Codility evidence

20 problems for Codility practice

Ranked by repeated public catalog sightings. Start with any problem below.
Show all problems

20 Codility practice problems loaded.

CompanyProblemDifficultyPublic evidenceAction
GOGoogle
Count Score CategoriesArraySimulationEasy7 public reportsLatest Oct 2026Practice
GOGoogle
Book Reading EveningsArrayGreedyEasy7 public reportsLatest Oct 2026Practice
COCapital One
Reconstruct Landmark JourneyGraphHash TableMedium4 public reportsLatest Sep 2026Practice
COCapital One
Compare Counts Around PivotArraySimulationEasy3 public reportsLatest Sep 2026Practice
DRDRW
Count Balanced Nodes in a Rooted TreeTreeDepth-First SearchMedium3 public reportsLatest Sep 2026Practice
DRDRW
Largest Number With Even Digit FrequenciesStringGreedyEasy3 public reportsLatest Sep 2026Practice
TITikTok
Count Skipped Numbers After SubtractionsArraySimulationEasy3 public reportsLatest Jul 2026Practice
HSHSBC
Distinct Products After Removing One ElementArrayHash TableEasy2 public reportsLatest Sep 2026Practice
DRDRW
Shortest Path Around Rectangular ObstaclesArrayMatrixMedium2 public reportsLatest Sep 2026Practice
TITikTok
Event ID Check Completion TimesArrayQueueMedium2 public reportsLatest Aug 2026Practice
MWMarshall Wace
Maximum Separation of Two Frogs on Adjacent BlocksArrayDynamic ProgrammingMedium2 public reportsLatest Feb 2023Practice
HSHSBC
Minimum Deletion Cost for Distinct Adjacent CharactersStringGreedyMedium1 public reportLatest Oct 2026Practice
JEJefferies
Maximum Income from Asset TradingArrayGreedyEasy1 public reportLatest Oct 2026Practice
JEJefferies
Repair a Binary SearchArrayBinary SearchEasy1 public reportLatest Oct 2026Practice
HSHSBC
Minimum Cleaning Robot RunsMatrixGraphMedium1 public reportLatest Sep 2026Practice
DRDRW
Shortest Compressed Length After RemovalStringPrefix SumMedium1 public reportLatest Jul 2026Practice
TITikTok
Count Cyclic Digit PairsArrayStringMedium1 public reportLatest Jun 2026Practice
TETesla
Count Zero-Sum FragmentsArrayPrefix SumMedium1 public reportLatest Jun 2026Practice
TETesla
Maximum Insertions Without Three Consecutive AStringGreedyMedium1 public reportLatest Jun 2026Practice
TETesla
Smallest Greater Integer With Same Digit SumMathSimulationEasy1 public reportLatest Jun 2026Practice
Showing 20 of 52 public Codility matchesShow all problems

  • Codility filter

    Start from explicitly supported platform evidence.

  • Constraints first

    Use input bounds to select a viable algorithm.

  • Run your code

    Check behavior in the FastPrep execution workspace.

  • Scale check

    Reason about time and space before finalizing.

Treat performance as part of correctness.

A solution is not finished when it passes one example. Build the habit of covering corner cases and choosing an approach that remains practical at the stated input limits.

  1. 01

    Define the full behavior

    Translate the prompt into invariants and list empty, minimal, repeated, and boundary inputs before implementation.

  2. 02

    Prove the complexity

    Estimate time and space from the maximum constraints, then reject approaches that cannot scale to those limits.

  3. 03

    Validate small and large cases

    Use readable examples for logic and custom cases for boundaries, degenerate inputs, and scale-sensitive behavior.

Turn the score goal into a preparation plan.

Review public company context, schedule focused correctness-and-performance sessions, and keep the actual assessment deadline visible in your application tracker.

Explore hiring insightsOpen the application tracker

Other assessment practice hubs

CodeSignal practiceHackerRank practiceKarat practice

What candidates should know.

What the filtered catalog can support, how to practice responsibly, and why constraints and edge cases matter.

01Is FastPrep affiliated with Codility?

No. FastPrep is an independent interview preparation and application tracking product. This page previews public catalog entries with explicit supporting Codility evidence.

02Does FastPrep provide official or private Codility tasks?

No. FastPrep does not provide official, private, leaked, or proprietary Codility tasks. The catalog is used for independent practice of transferable problem-solving skills.

03How are Codility practice problems selected?

FastPrep previews up to 20 public assessment problems with explicit Codility evidence, ordered by repeated public catalog sightings. The filtered problem bank shows the complete available set.

04What should a Codility-style practice session emphasize?

Start from the constraints, identify corner cases, state the expected time and space complexity, implement, and test both small examples and boundary inputs. Follow the rules in your actual assessment invitation.

05How can I see every Codility practice problem?

Select Show all problems above or below the preview table. The full problem list opens with the Codility filter already applied.

Your next useful action

Make one solution hold up.

Choose a problem, cover the boundaries, and verify the complexity before moving on.

View practice problems