Duolingo interview practice
Duolingo online assessment and coding practice Start with verified evidence.
Practice from 26 Duolingo-tagged public coding problems, organized only by the stage, topic, difficulty, and recency metadata FastPrep can verify.
- Catalog
- 26 public practice assets (26 coding)
- Start here
- Use the stage named in your invitation
- Evidence
- OA · Phone · Onsite metadata, shown in context
OA practice path
Online Assessment
Build a timed implementation rhythm from prompt to edge cases. Problems are ranked by repeated public catalog sightings.
| Company | Problem | Difficulty | Public evidence | Action |
|---|---|---|---|---|
DUDuolingo | Shortest Route Through a Traced MazeGraphBreadth-First Search | Medium | 5 public reportsLast reported Sep 2022 | Practice |
DUDuolingo | Rank Common Translation MistakesHash TableSorting | Medium | 4 public reportsLast reported Sep 2022 | Practice |
DUDuolingo | Most-Read Page Across Every Valid StorylineGraphBacktracking | Hard | 2 public reportsLast reported Oct 2022 | Practice |
DUDuolingo | Collect Sticks for a Bird's NestArrayTwo Pointers | Medium | 1 public reportLast reported Oct 2025 | Practice |
DUDuolingo | Dynamic Pair Sum QueriesArrayHash Table | Medium | 1 public reportLast reported Oct 2025 | Practice |
DUDuolingo | Longest Border-Ending Diagonal PatternMatrixDynamic Programming | Medium | 1 public reportLast reported Oct 2025 | Practice |
DUDuolingo | Bouncing Square Reaches a Screen CornerSimulationMath | Medium | 1 public reportLast reported Dec 2024 | Practice |
DUDuolingo | Construct New ArrayArrayTwo Pointers | Easy | 1 public reportLast reported Oct 2024 | Practice |
DUDuolingo | Longest Stable Transaction PeriodArrayPrefix Sum | Medium | 1 public reportLast reported Oct 2024 | Practice |
DUDuolingo | Replace Nth ConsonantString | Easy | 1 public reportLast reported Oct 2024 | Practice |
DUDuolingo | Count Distinct Word MeaningsStringHash Table | Medium | 1 public reportLast reported Sep 2021 | Practice |
DUDuolingo | Count Legal Outfit CombinationsArrayBacktracking | Medium | 1 public reportLast reported Sep 2021 | Practice |
Phone practice path
Phone Screen
Practice solving while explaining assumptions, tradeoffs, and complexity. Problems are ranked by repeated public catalog sightings.
13 Duolingo-tagged Phone Screen problems available.
| Company | Problem | Difficulty | Public evidence | Action |
|---|---|---|---|---|
DUDuolingo | Visit Desired Attractions Without Reusing a TrailGraphDepth-First Search | Hard | 3 public reportsLast reported Oct 2026 | Practice |
DUDuolingo | Most-Read Page Across Every Valid StorylineGraphBacktracking | Hard | 2 public reportsLast reported Oct 2022 | Practice |
DUDuolingo | Correct an In-Place Array ReversalArrayTwo Pointers | Easy | 1 public reportLast reported Oct 2026 | Practice |
DUDuolingo | Count Starts Reaching a Grid MaximumMatrixDepth-First Search | Medium | 1 public reportLast reported Oct 2026 | Practice |
DUDuolingo | Select the Top User MatchesArrayHeap | Medium | 1 public reportLast reported Oct 2026 | Practice |
DUDuolingo | Sum All Values in a Binary TreeTreeDepth-First Search | Easy | 1 public reportLast reported Oct 2026 | Practice |
DUDuolingo | User Resource Transition ProbabilitiesArrayHash Table | Medium | 1 public reportLast reported Oct 2026 | Practice |
DUDuolingo | Return Every Matching DecryptionStringHash Table | Medium | 1 public reportLast reported Apr 2026 | Practice |
DUDuolingo | Encrypt and Decrypt StringsStringHash Table | Medium | 1 public reportLast reported Apr 2026 | Practice |
DUDuolingo | Validate a Mahjong Hand PartitionArrayBacktracking | Medium | 1 public reportLast reported Nov 2025 | Practice |
DUDuolingo | Directional Tiles: Find a Valid Reconfiguration PathArrayGraph | Medium | 1 public reportLast reported Oct 2022 | Practice |
DUDuolingo | Find Every Reachable Derived Vocabulary WordStringGraph | Medium | 1 public reportLast reported Sep 2021 | Practice |
DUDuolingo | Maximum-Value Word Derivation PathGraphDynamic Programming | Medium | 1 public reportLast reported Sep 2021 | Practice |
Onsite practice path
Onsite
Practice complete solutions and defend the choices behind them. Problems are ranked by repeated public catalog sightings.
| Company | Problem | Difficulty | Public evidence | Action |
|---|---|---|---|---|
DUDuolingo | Rank Word-Translation Hints from Sentence TranslationsStringSorting | Medium | 2 public reportsLast reported Apr 2026 | Practice |
DUDuolingo | Longest Decreasing Matrix Path with Limited RelaxationsMatrixGraph | Hard | 1 public reportLast reported Nov 2025 | Practice |
01 · Preparation plan
Turn two pointers, prefix state, and string indexing into a deliberate practice loop.
Duolingo's current OA-tagged evidence is best used as a timed fundamentals circuit that alternates array movement, prefix-state bookkeeping, and careful character classification. Catalog labels guide practice but do not promise a current or universal hiring loop. This is a suggested practice sequence, not the employer's interview process. Your invitation and recruiter guidance remain the source of truth.
- 01
Practice Construct New Array
Use Construct New Array to rehearse two-pointer array transformation. Keep the exercise's published contract separate from assumptions about Duolingo's current interview process.
- Restate the exact input, output, and constraints for two-pointer array transformation.
- Explain the data structure and complexity before completing the implementation.
- Test a boundary case, a repeated-value case, and the smallest valid input.
- 02
Practice Longest Stable Transaction Period
Use Longest Stable Transaction Period to rehearse prefix-state interval detection. Keep the exercise's published contract separate from assumptions about Duolingo's current interview process.
- Restate the exact input, output, and constraints for prefix-state interval detection.
- Explain the data structure and complexity before completing the implementation.
- Test a boundary case, a repeated-value case, and the smallest valid input.
- 03
Practice Replace Nth Consonant
Use Replace Nth Consonant to rehearse string indexing under character rules. Keep the exercise's published contract separate from assumptions about Duolingo's current interview process.
- Restate the exact input, output, and constraints for string indexing under character rules.
- Explain the data structure and complexity before completing the implementation.
- Test a boundary case, a repeated-value case, and the smallest valid input.
02 · Evidence boundary
What “Duolingo interview questions” means here.
It means practicing transferable implementation, testing, and technical reasoning with public catalog assets FastPrep tags to Duolingo. It does not mean FastPrep has access to the company's assessments or any private interview bank.
Repeated public sightings and last-reported dates can help you prioritize practice, but they cannot predict the questions, format, or platform in a specific interview.
- Only Duolingo-tagged FastPrep catalog problems appear above.
- Stage labels and report dates remain visible as context.
- No official, private, leaked, or proprietary questions are claimed.
03 · Plain answers
Duolingo interview practice questions, answered plainly.
This page owns technical-practice intent for Duolingo. Hiring activity, timelines, and market signals remain on the separate hiring-insights page.
01What evidence supports this Duolingo interview practice page?
The launch review verified 3 coding exercises (3 total public practice items). The strongest reviewed themes are two-pointer array transformation, prefix-state interval detection, string indexing under character rules. Counts and report labels can change, so use this as a focused practice library and follow your own invitation for the current format, timing, and permitted tools.
02Is FastPrep affiliated with Duolingo?
No. FastPrep is an independent interview-preparation product and is not affiliated with Duolingo. The page uses FastPrep's public practice catalog and does not claim official, private, leaked, or proprietary employer questions.
03How are Duolingo problems assigned to interview stages?
Stage labels come from FastPrep's public problem metadata. A problem can carry more than one reported stage, and hiring processes can change by role, level, location, and date. Treat the labels as preparation context, not a guarantee.
04Which Duolingo interview stage should I practice first?
Start with the stage named in your invitation or recruiter message. If no stage is known, use the largest available set to build general problem-solving fluency, then rehearse explanation and testing separately.
05Does this page predict the Duolingo interview process?
No. Public catalog counts, stage tags, and last-reported dates can help prioritize practice, but they cannot predict a specific interview's questions, sequence, timing, or platform.
Your next stage, made concrete
Pick a problem. Solve it end to end.
Start with the stage named in your invitation, then use public evidence as context—not as a promise of what you will be asked.
Open the practice set