Drills

Comparison questionHard~10 min

When would you use Angular signals instead of RxJS Observables?

Chooses between synchronous UI state and asynchronous event streams without treating either model as a replacement for the other.

AngularRxJSTypeScript

When would you use a Protocol instead of an abstract base class in Python?

Chooses structural or nominal contracts based on ownership, runtime identity, shared behavior, and third-party integration.

Comparison questionEasy~5 min

When would you use a ref instead of state in React?

Distinguishes render-driving state from instance-local mutable values and DOM references.

ReactTypeScript

Comparison questionHard~10 min

When would you use a Server Action instead of a Route Handler?

Chooses between UI-coupled mutations and explicit HTTP contracts without treating either as a hidden trust boundary.

Next.jsReactTypeScript

Artificial IntelligenceGenerative AILarge Language Models

When would you use a smaller model instead of the most capable one?

Uses task bounds and evaluation evidence to choose smaller models for lower latency, cost, capacity, privacy, or local execution.

When would you use asyncio Lock, Event, Condition, or Semaphore?

Chooses task synchronization by protected state, notification predicates, and limited capacity.

Comparison questionHard~15 min

When would you use asyncio.TaskGroup or asyncio.gather()?

Compares structured task ownership with ordered result aggregation and different failure behavior.

Comparison questionHard~15 min

When would you use asyncio.to_thread() or run_in_executor()?

Compares convenient context-propagating thread offload with explicit executor selection and ownership.

Artificial IntelligenceGenerative AILarge Language Models

When would you use deterministic checks, model graders, or human review?

Matches exact checks, model judgment, and human expertise to the behavior being measured instead of treating graders as interchangeable.

When would you use Django select_related or prefetch_related?

Chooses Django relationship loading from relationship shape, result cardinality, and measured query behavior.

DjangoPython

When would you use FastAPI TestClient versus an async HTTP client?

Chooses synchronous or asynchronous FastAPI test clients from the boundary exercised and resources involved.

FastAPIpytestPython

When would you use HashMap, LinkedHashMap, or TreeMap?

Chooses among common Java map implementations by lookup behavior, iteration order, sorting, range operations, and key contracts.

Java

Concept questionMedium~7 min

When would you use input, output, or model signals in Angular?

Distinguishes one-way data, events, and deliberate two-way component contracts without hiding ownership.

AngularRxJSTypeScript

When would you use minimal APIs in ASP.NET Core?

Explains minimal APIs, endpoint groups, dependency injection, typed results, filters, and when they fit real services.

.NETASP.NET CoreC#

Artificial IntelligenceGenerative AILarge Language Models

When would you use pairwise comparison instead of absolute scoring?

Uses pairwise judgments for relative change and absolute criteria for release obligations while controlling order and verbosity bias.

When would you use Promise.all, allSettled, race, or any?

Chooses promise combinators by success criteria, failure semantics, cancellation needs, and the fate of losing operations.

JavaScript

Artificial IntelligenceGenerative AILarge Language ModelsVector Databases

When would you use RAG instead of a database query or tool call?

Chooses retrieval for ambiguous knowledge search while keeping authoritative structured operations behind deterministic services.

Concept questionHard~9 min

When would you use Span, Memory, or ArrayPool in .NET?

Introduces lower-level allocation tools while emphasizing measurement, ownership, and safe usage.

.NETASP.NET CoreC#

When would you use Spring application events instead of durable messaging?

Separates in-process decoupling from durable cross-process delivery and makes timing, failure, and transaction expectations explicit.

JavaSpring Boot

When would you use SQLAlchemy ORM, SQLAlchemy Core, or raw SQL?

Chooses a SQLAlchemy abstraction from the work's shape instead of performance slogans.

PythonSQLAlchemy

When would you use `useLayoutEffect` instead of `useEffect`?

Chooses post-paint synchronization by default and reserves layout effects for pre-paint measurement or correction.

ReactTypeScript