A trie stores strings as paths of characters; each edge represents a character. Prefix queries are efficient because all words with the same prefix share the same path, so lookup is O(L) where L is the key length. The trade‑off is higher memory usage compared to hashing.
Advanced answer
Deep dive
Expanding on the short answer — what usually matters in practice:
Complexity: compare typical operations (average vs worst-case).
Invariants: what must always hold for correctness.
When the choice is wrong: production symptoms (latency, GC, cache misses).
Explain the "why", not just the "what" (intuition + consequences).
Trade-offs: what you gain/lose (time, memory, complexity, risk).
Edge cases: empty inputs, large inputs, invalid inputs, concurrency.
Examples
A tiny example (an explanation template):
// Example: discuss trade-offs for "what-is-a-trie-and-why-is-it-good-for-prefix-sea"
function explain() {
// Start from the core idea:
// A trie stores strings as paths of characters; each edge represents a character. Prefix que
}
Common pitfalls
Too generic: no concrete trade-offs or examples.
Mixing average-case and worst-case (e.g., complexity).