Problem database last updated: June 20, 2025
3 problems · 1 Easy, 1 Medium, 1 Hard · Ranked #362 of 458
1 Easy
33% · avg 23%
1 Medium
33% · avg 59%
1 Hard
33% · avg 18%
Based on 3 reported problems, Toptal interviews are significantly harder than average - 33% Hard vs 18% across all companies.
Compared to the industry average, Toptal puts unusual emphasis on dynamic-programming (66.7% of problems, 3.4x the industry average). If you're short on time, these are the categories to double down on.
The most common topics are dynamic-programming (66.7%), string (33.3%), math (33.3%), brainteaser (33.3%). Problems below are sorted by frequency, the ones at the top are asked most often.
| Problem | Difficulty | Frequency | Topics | |
|---|---|---|---|---|
String Compression II Run-length encoding is a string compression method that works by replacing consecutive identical characters (repeated 2 or more times) with the concatenation of... | Hard | Very Likely | stringdynamic-programming | Solve |
Airplane Seat Assignment Probability n passengers board an airplane with exactly n seats. The first passenger has lost the ticket and picks a seat randomly. But after that, the rest of the passenge... | Medium | Likely | mathdynamic-programmingbrainteaser | Solve |
Image Smoother An image smoother is a filter of the size 3 x 3 that can be applied to each cell of an image by rounding down the average of the cell and the eight surrounding... | Easy | Likely | arraymatrix | Solve |
String Compression II
SolveRun-length encoding is a string compression method that works by replacing consecutive identical characters (repeated 2 or more times) with the concatenation of...
Airplane Seat Assignment Probability
Solven passengers board an airplane with exactly n seats. The first passenger has lost the ticket and picks a seat randomly. But after that, the rest of the passenge...
Image Smoother
SolveAn image smoother is a filter of the size 3 x 3 that can be applied to each cell of an image by rounding down the average of the cell and the eight surrounding...
Frequency scores are based on crowdsourced interview reports. A higher score means the problem has been reported more often in recent Toptal interviews.
Very Likely
75-100%
Likely
50-74%
Sometimes
25-49%
Rare
0-24%
Toptal interviews focus heavily on dynamic-programming, string, math problems. If you're short on time, these are the categories to prioritize. The problems on this page are sorted by frequency, so start from the top and work your way down.
Beyond solving problems, practice explaining your approach. Toptal interviewers care about your thought process - how you break down a problem, consider edge cases, and evaluate tradeoffs between solutions. A clean O(n) solution you can explain clearly beats an O(log n) solution you can't articulate.
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Toptal has been reported to ask 3 distinct coding problems. The most common topics are dynamic-programming, string, math. 1 are Easy difficulty, 1 are Medium, and 1 are Hard. Problems are sorted by frequency - the ones at the top are asked most often.
Based on 3 reported problems, Toptal interviews are significantly harder than average - 33% Hard vs 18% across all companies. 33% of questions are Medium difficulty. Focus on the high-frequency Medium problems first, then work through the Hard ones.
Start with the highest-frequency problems listed on this page. Focus on the core topics: dynamic-programming, string, math. Practice solving them under time pressure and explaining your approach out loud. Mock interviews with AI can simulate the real experience.
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