Domain-Specific Knowledges Flashcards
7 cards from real CodeSignal Technical Assessment practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Domain-Specific Knowledges flashcards as text
What is the primary advantage of using an index on a database column?
Answer: Speeds up SELECT queries at the cost of slower writes
Indexes create auxiliary data structures that accelerate reads but must be maintained on every insert, update, or delete.
In JavaScript, what does the event loop's 'microtask queue' hold, and when does it drain?
Answer: Promise callbacks (.then/.catch); after the current task completes, before the next macrotask
Microtasks (Promise continuations, queueMicrotask) drain completely after each macrotask and before the next macrotask begins.
Which TCP mechanism prevents a fast sender from overwhelming a slow receiver?
Answer: Flow control via the receive window
TCP flow control uses the receiver-advertised window size (rwnd) to limit how much data the sender can have in-flight at once.
In Python, what is the time complexity of checking whether an element exists in a set?
Answer: O(1) average
Python sets are implemented as hash tables, so membership tests are O(1) on average, O(n) in the degenerate collision case.
Which design pattern defines a family of algorithms, encapsulates each one, and makes them interchangeable at runtime?
Answer: Strategy
The Strategy pattern lets you select an algorithm at runtime by programming to an interface rather than a concrete class.
What is 'eventual consistency' in distributed systems?
Answer: Given no new writes, all replicas will converge to the same value over time
Eventual consistency guarantees convergence in the absence of further updates but does not specify when or impose a strict time bound.
In React, what triggers a component to re-render?
Answer: Changes to state or props, or a parent re-render
React schedules re-renders when setState is called, when received props change, or when the parent component re-renders (unless memoized).