Big-O for core operations

What you’ll practice

Big-O for core operations is where interview prep meets real-world coding: insert, delete, search, access, traversal, and resizing across arrays, linked lists, stacks, queues, hash tables, heaps, and trees.

Each question uses 4 options and there’s no timer, so you can slow down and reason about best/average/worst cases without pressure.

How difficulty and length are balanced

The quiz is Mixed difficulty by design: you’ll get a blend of quick wins (like O(1) access patterns) and trickier comparisons (like amortized vs worst-case). Choose your question count and difficulty before starting—short sets for warm-ups, longer runs for endurance and retention.

Common pitfalls to avoid

Many wrong answers come from mixing up average vs worst case, forgetting amortized costs (dynamic arrays, hash table rehashing), or assuming “sorted” without being told.

Watch for hidden steps like traversal before deletion, collision handling, and whether an operation needs shifting or re-linking.

Tips to score higher

• Separate time vs space complexity when you reason about an operation
• Ask yourself: does this require scanning, shifting, rebalancing, or resizing?
• Remember amortized analysis for dynamic arrays and hash tables
• For trees, check whether the structure is balanced or can degrade
• Don’t assume O(1) hashing means O(1) in the worst case