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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
22 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
COCapital One
Compare Counts Around PivotArraySimulationEasy2 public reportsLatest Jul 2026Practice
COCapital One
Reconstruct Landmark JourneyGraphHash TableMedium2 public reportsLatest Jul 2026Practice
TITiktok
Count Skipped Numbers After SubtractionsArraySimulationEasy2 public reportsLatest Jul 2026Practice
DRDRW
Shortest Compressed Length After RemovalStringPrefix SumMedium1 public reportLatest Jul 2026Practice
TITiktok
Count Cyclic Digit PairsArrayStringMedium1 public reportLatest Jun 2026Practice
TITiktok
Event ID Check Completion TimesArrayQueueMedium1 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
DRDRW
Simplified Tetris EngineSimulationMatrixHard1 public reportLatest Mar 2026Practice
YAYahoo
Modify the StringStringGreedyMedium1 public reportLatest Mar 2025Practice
YAYahoo
Count Binary SubstringsStringTwo PointersEasy1 public reportLatest Mar 2025Practice
HSHSBC
Arrange Flower SticksArraySortingEasy1 public reportLatest Mar 2025Practice
HSHSBC
Find Largest House AreaMatrixDepth-First SearchEasy1 public reportLatest Mar 2025Practice
TETesla
EncryptStringMathEasy1 public reportLatest Mar 2025Practice
TETesla
Maximum Number of Workers with Equal Left and Right ShoesStringPrefix SumEasy1 public reportLatest Mar 2025Practice
TMTrend Micro
Change Segment ColorsTreeGraphHard1 public reportLatest Dec 2024Practice
TMTrend Micro
Counting GameMathSimulationMedium1 public reportLatest Dec 2024Practice
GIGithub
Bridge Car Weight ProblemGreedyDynamic ProgrammingHard1 public reportLatest Dec 2024Practice
TMTrend Micro
Find SequencesMathSimulationMedium1 public reportLatest Aug 2024Practice
Showing 20 of 22 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