Data structures: arrays, lists, and trees

What this quiz covers

Arrays, lists, and trees show up everywhere in coding interviews and everyday programming, and this quiz focuses on the essentials you actually use. Expect questions that connect concepts to real operations like searching, inserting, deleting, and traversing.

Each question gives 4 options and there’s no timer, so you can reason through complexity and edge cases instead of rushing. You can also choose the question count and difficulty before you start, making it easy to do a quick refresher or a longer session.

Skills you’ll practice

You’ll strengthen your ability to predict runtime and memory trade-offs, spot the right structure for a task, and follow how data moves through common operations. The mixed difficulty balances straightforward definitions with scenario-based questions that require careful thinking.

• Big-O reasoning for access, search, insert, and delete across structures
• Array indexing vs. list traversal and their practical consequences
• Tree terminology (root, leaf, height, depth) and traversal patterns
• Recognizing when balancing matters and what it changes conceptually
• Identifying correct edge-case behavior (empty, single-node, duplicates)

Common pitfalls and how difficulty is balanced

Many mistakes come from mixing up constant-time access with constant-time insertion, or assuming trees are always fast without considering shape. The quiz mixes easy recall questions with medium and harder “choose the best structure” items, so you build confidence while still getting challenged.

If you want a gentler run, choose fewer questions or an easier setting; for a deeper workout, increase the question count and keep difficulty on Mixed. Because there’s no timer, you can review why an option is wrong and learn the pattern behind it.