Anduril Coding Interview Questions
25 Anduril coding interview problems with full optimal solutions — 8 easy, 12 medium, 5 hard. Every problem ships with multiple approaches (brute-force first, then the optimal), complexity tables for each, company-specific tips on what an Anduril interviewer values, and a FAQ section.
Showing 10 problems of 25
- #3mediumfrequently asked
3. Longest Substring Without Repeating Characters
Find the length of the longest substring with all unique characters. Anduril uses this classic sliding-window problem to test whether you can maintain a dynamic window with O(1)-lookup membership — the same pattern appears in rate-limiting command queues and deduplicating real-time event streams on autonomous platforms.
- #15mediumfrequently asked
15. 3Sum
Find all unique triplets in an array that sum to zero. Anduril uses this to test whether you can reduce a multi-pointer problem to sorted-array two-pointer reasoning and rigorously eliminate duplicates — the same discipline required when deduplicating redundant sensor readings in a fusion pipeline.
- #56mediumfrequently asked
56. Merge Intervals
Merge all overlapping intervals in a list. Anduril asks this because interval merging is a real problem in mission scheduling and time-window conflict resolution for autonomous systems — you need to sort, then reason carefully about edge cases where intervals share an endpoint.
- #146mediumfrequently asked
146. LRU Cache
Design a Least Recently Used cache with O(1) get and put. Anduril frequently asks this because caching is a building block of real-time command pipelines — you need to compose a hash map and a doubly-linked list correctly and articulate why both structures are necessary.
- #200mediumfrequently asked
200. Number of Islands
Count the number of distinct land masses in a binary grid. Anduril asks this because graph traversal on a grid is the foundation of obstacle-map parsing and terrain-segmentation algorithms used in autonomous navigation — engineers need to demonstrate clean BFS/DFS reasoning on 2D state spaces.
- #207mediumfrequently asked
207. Course Schedule
Determine whether all courses can be completed given their prerequisites — in other words, detect whether a directed graph contains a cycle. Anduril tests this because dependency cycle detection is fundamental to build system safety, firmware task scheduling, and verifying that mission plans are acyclic before execution.
- #215mediumfrequently asked
215. Kth Largest Element in an Array
Find the kth largest element without fully sorting the array. Anduril asks this to see whether you know Quickselect — an O(n) average-time selection algorithm that demonstrates in-place partitioning discipline, the same technique used in real-time ranking systems for sensor-priority queues.
- #238mediumfrequently asked
238. Product of Array Except Self
Compute for each index the product of all other elements without using division. Anduril asks this to verify you can maintain running prefix and suffix state in a single-pass — a technique that appears in sensor-normalization pipelines where you need context from both sides of a measurement without reprocessing the full array.
- #322mediumfrequently asked
322. Coin Change
Find the minimum number of coins needed to make up a given amount. Anduril uses this classic 1D DP problem to assess whether you can define the right subproblem, initialize boundary conditions correctly, and reason about infeasible states — the same structured thinking needed when minimizing resource usage in constrained mission planning.
- #347mediumfrequently asked
347. Top K Frequent Elements
Return the k most frequently occurring integers in an array. Anduril asks this to test whether you know the O(n) bucket-sort approach versus the O(n log k) heap — the same frequency-ranking logic drives mission-critical log triage and alert deduplication in real-time systems.