A singly linked list stores only `next`, so it uses less memory and is simpler. A doubly linked list stores `prev` and `next`, which makes removing a known node and iterating backwards easier, but costs more memory and pointer updates. Choose singly when you only need forward traversal; choose doubly when you frequently remove nodes in the middle or need reverse traversal.
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 "singly-vs-doubly-linked-list:-when-would-you-cho"
function explain() {
// Start from the core idea:
// A singly linked list stores only `next`, so it uses less memory and is simpler. A doubly l
}
Common pitfalls
Too generic: no concrete trade-offs or examples.
Mixing average-case and worst-case (e.g., complexity).