Coinbase Coding Interview Questions
28 Coinbase coding interview problems with full optimal solutions — 16 easy, 9 medium, 3 hard. Every problem ships with multiple approaches (brute-force first, then the optimal), complexity tables for each, company-specific tips on what an Coinbase interviewer values, and a FAQ section.
Showing 10 problems of 28
- #4easysometimes asked
4. Remove Duplicates from Sorted Array
Compact a sorted array in place so each element appears once and return the new length. Coinbase uses this to probe pointer-discipline — the same two-pointer trick deduplicates trade prints with the same sequence number.
- #5easysometimes asked
5. Remove Element
Remove all occurrences of a target value from an array in place. Coinbase uses this as a quick filter to confirm you reach for two-pointer compaction before allocating.
- #8easysometimes asked
8. Plus One
Increment a big integer represented as a digit array by one. Coinbase uses this as a warm-up before the inevitable BigInt and precision-handling follow-ups.
- #10easysometimes asked
10. Binary Tree Inorder Traversal
Return the inorder traversal of a binary tree's values. Coinbase asks this to confirm you can do both recursive and iterative tree walks — iterative is the one you'd use to walk a price-level tree without blowing the stack.
- #11easysometimes asked
11. Same Tree
Determine whether two binary trees are structurally identical with equal values. Coinbase asks this as a warm-up for tree-equivalence and snapshot-comparison follow-ups.
- #12easyrarely asked
12. Symmetric Tree
Check whether a binary tree is a mirror of itself. Coinbase uses this to confirm you can recurse on pairs — the same pattern used to compare a bid ladder with its ask mirror.
- #13easysometimes asked
13. Maximum Depth of Binary Tree
Return the depth of a binary tree. Coinbase uses this to verify recursion fundamentals before moving to harder tree problems.
- #14easysometimes asked
14. Balanced Binary Tree
Determine if a binary tree is height-balanced. Coinbase uses this to test the post-order short-circuit pattern — the same trick used to validate constraints across an order-book tree.
- #15easyrarely asked
15. Minimum Depth of Binary Tree
Return the minimum depth — the number of nodes along the shortest path from root to nearest leaf. Coinbase asks this to test whether you spot the asymmetric edge case where one child is null.
- #16easyrarely asked
16. Pascal's Triangle
Generate the first numRows of Pascal's triangle. Coinbase asks this to test array-building discipline and to set up follow-ups on combinatorics (used in risk-pricing).
Related interview-prep guides
CodeInterview.io Live Coding Interview Guide (2026): What the Platform Tracks and How to Walk Through It Cleanly
CodeInterview.io is a browser-based collaborative live-coding platform. Think of it as a lighter-footprint alternative to CoderPad with an integrated video call, per-keystroke replay, and a drawing whiteboard. Smaller market share than CoderPad but shows up at a meaningful slice of YC startups and mid-market tech teams in 2026. This is what CodeInterview.io tracks, how its all-in-one workflow compares to CoderPad, and how to walk through a live round cleanly.
Interview Coder & 'Stealth' Coding Tools in 2026: What They Really Do, What They Risk, and Why Honest Prep Wins
Tools sold as 'stealth' coding assistants are desktop overlays and browser extensions that read a live coding question and suggest AI answers in a window hidden from the screen share. The 2026 reality: hiding a window does not make anyone undetectable, using one against a company's rules is cheating, the offer-rescission risk is real, and the candidates who land jobs build the skill before the round. This guide covers what these tools really do, what a hidden window does not change, the legal and blacklist landscape, four habits from these tools that DO work for honest prep, and what to use instead if you want to actually get hired.
Beyz AI Alternatives in 2026: 7 Tools Compared (Screenshot + Overlay Helpers)
Beyz AI is a screenshot-and-clipboard interview helper that shows AI answers in an overlay window that hides from screen share, built for use during online assessments and live rounds. The 2026 reality: candidates search for alternatives because of the $30+/month price tag with feature ceilings, the narrow scope (coding-OA-shaped use only), and second thoughts about using a helper during tests at all. This guide ranks the 7 best Beyz AI alternatives, with InterviewChamp.AI compared honestly alongside, plus how to pick based on your specific interview gauntlet.