Coinbase Coding Interview Questions

Showing 18 problems of 28

• #17mediumfoundational

  17. Top K Frequent Elements

  Surface the K most-traded assets on an exchange — Coinbase uses this problem to test whether you reach for a heap over a naive sort when ranking trade volumes across thousands of instruments.

  Solve →
• #18mediumfoundational

  18. Coin Change

  Compute the fewest denominations to reach an exact value — Coinbase uses this DP classic to see how you model currency conversion and minimum-fee routing across crypto denominations.

  Solve →
• #19mediumfoundational

  19. Merge Intervals

  Collapse overlapping trading windows into consolidated ranges — Coinbase uses interval merging to evaluate how engineers reason about time-series events like order-book snapshots and candlestick aggregation.

  Solve →
• #20mediumfoundational

  20. Min Stack

  Track the minimum portfolio value at O(1) cost — Coinbase asks this to test whether you can maintain auxiliary state for instant low-watermark reads without rescanning the full price history.

  Solve →
• #21mediumfoundational

  21. LRU Cache

  Build a fixed-capacity account-data cache that evicts the least-recently-used entry — Coinbase uses this design question to measure whether you can combine a hash map and a doubly-linked list for O(1) reads and writes.

  Solve →
• #22mediumfoundational

  22. Number of Islands

  Count disconnected clusters in a grid — Coinbase maps this to partitioning liquidity pools or detecting isolated market segments that cannot route to a shared settlement layer.

  Solve →
• #23hardfoundational

  23. Sliding Window Maximum

  Extract the peak price across every k-candle trading window in O(n) — Coinbase uses this problem to stress-test whether you can maintain a monotonic deque instead of repeatedly scanning a window when computing rolling highs on order-book snapshots.

  Solve →
• #24hardfoundational

  24. Trapping Rain Water

  Calculate total liquidity trapped between price-bar barriers — Coinbase uses this classic to evaluate whether engineers can reason about prefix/suffix maximums and then collapse the solution to a two-pointer scan without extra arrays.

  Solve →
• #25mediumfoundational

  25. Longest Substring Without Repeating Characters

  Find the longest run of unique trading-pair symbols in a sequence — Coinbase uses sliding-window problems to evaluate how you model streaming data with a shrinking-left-boundary technique common in real-time feed deduplication.

  Solve →
• #26mediumfoundational

  26. K Closest Points to Origin

  Retrieve the K accounts with the smallest distance from a reference price level — Coinbase uses this heap problem to test real-time top-K selection, the engine behind their order-proximity ranking in the matching engine.

  Solve →
• #27mediumfoundational

  27. Network Delay Time

  Find the worst-case latency before a broadcast reaches every node — Coinbase uses Dijkstra problems to evaluate how engineers reason about minimum-cost routing across crypto-network relay nodes and cross-chain bridging hops.

  Solve →
• #28hardfoundational

  28. Find Median from Data Stream

  Maintain the real-time median bid price as orders stream in — Coinbase uses this dual-heap problem to test whether engineers can design O(log n) insert / O(1) median structures for continuous market-data feeds.

  Solve →
• #1easyfrequently asked

  1. Two Sum

  Given an array of integers and a target, return the indices of two numbers that add up to the target. Coinbase asks this as a warm-up to gauge whether you reach for hash maps over nested loops on the very first problem.

  Solve →
• #2easyfrequently asked

  2. Valid Parentheses

  Determine if a string of brackets is balanced and properly nested. Coinbase uses this to test stack fundamentals — order-book matching engines lean on the same LIFO discipline.

  Solve →
• #3easyfrequently asked

  3. Merge Two Sorted Lists

  Splice two sorted linked lists into one sorted list. Coinbase uses this to test pointer manipulation — a common building block when merging streams of order-book updates from different feeds.

  Solve →
• #6easyfrequently asked

  6. Search Insert Position

  Given a sorted array, find the index where a target should be inserted to maintain order. Coinbase asks this because it's the building block for inserting a new limit order at the right price level in an order book.

  Solve →
• #7easyfrequently asked

  7. Maximum Subarray

  Find the contiguous subarray with the largest sum. Coinbase asks this to test the local-vs-global pattern — the same shape shows up when finding the most profitable contiguous holding window in price data.

  Solve →
• #9easyfrequently asked

  9. Merge Sorted Array

  Merge two sorted arrays in place, with nums1 sized large enough to hold both. Coinbase asks this because in-place merges show up everywhere in matching engines — the destination buffer is already allocated.

  Solve →