44 questions
Problem solving interview questions
Estimation, debugging, concurrency and trade-off questions — the prompts that surface inside coding and design rounds rather than as a round of their own.
These are where interviewers separate levels: the same answer at two depths reads very differently. Problem statements, examples and hints are free on every page; the worked approach and solution are in the company guides.
- Amortized Cost of a Dynamic Array
- Binary Search Off-by-One
- Bounded Blocking Queue
- Break Down a Latency Budget
- Closure Late Binding in a Loop
- Consistent Hashing Explained
- Convert DAU to Concurrent Users
- Dining Philosophers Deadlock
- Estimate CDN Bandwidth for a Live Event
- Estimate Daily Storage for Video Uploads
- Estimate Email Storage for a Billion Users
- Estimate Log Volume per Day
- Estimate Memory for a URL Cache
- Estimate Search Engine QPS
- Estimate Servers for an API Load
- Estimate the Cost of Storing Photos
- False Sharing and Cache Lines
- Floating-Point Equality
- Hash Table Worst Case and Mitigation
- Integer Overflow in Midpoint
- is vs ==
- LSM Tree vs B-Tree
- Modifying a List While Iterating
- Mutable Default Argument
- Mutable Object as a Dict Key
- Pick the Data Structure for Each Scenario
- Predict the Output - Generator Laziness
- Predict the Output - Python Scoping
- Print in Order with Threads
- Process vs Thread vs Coroutine
- Quadratic String Building
- Read-Write Lock
- Recursion Depth Exceeded
- Recursion vs Iteration and Memory
- Shallow Copy of a Nested List
- Sorting Nearly Sorted Input
- TCP vs UDP: Choose for a Scenario
- Thread-Safe Counter
- Timezone-Naive Datetime
- Token Bucket Rate Limiter Class
- Unicode String Length
- Unstable Sort Assumption
- What Happens When You Load a URL
- When n² Beats n log n
Free starter pack
13 must-tier questions with full solutions
Sign in with an email, no purchase, and read them in the full reader.