Roblox Coding Interview Questions
26 Roblox coding interview problems with full optimal solutions — 16 easy, 8 medium, 2 hard. Every problem ships with multiple approaches (brute-force first, then the optimal), complexity tables for each, company-specific tips on what an Roblox interviewer values, and a FAQ section.
Showing 8 problems of 26
- #15mediumfoundational
15. Number of Islands
Count connected land regions in a binary grid — Roblox uses this pattern to identify distinct terrain chunks when generating and streaming open-world maps to millions of concurrent players.
- #18mediumfoundational
18. Course Schedule
Detect cycles in a directed prerequisite graph to determine if all courses can be finished — Roblox applies the same topological-sort logic to resolve asset-loading dependency chains in its streaming engine.
- #19mediumfoundational
19. Word Search
Find whether a word exists in a 2D character grid following adjacent cells — Roblox uses the same constrained-path DFS to validate item-placement patterns and check chat-filter word formations across tiled regions.
- #20mediumfoundational
20. LRU Cache
Design a fixed-capacity cache that evicts the least recently used item — the exact structure Roblox's asset server uses to keep hot game assets in memory while dropping stale ones as thousands of players load different virtual worlds.
- #21mediumfoundational
21. Top K Frequent Elements
Return the k most frequent values from an array — Roblox uses this pattern to surface trending game items, rank popular avatar accessories, and identify the most-crashed experiences from telemetry event streams.
- #22mediumfoundational
22. Implement Trie (Prefix Tree)
Build a prefix tree supporting insert, search, and startsWith — Roblox applies tries for autocomplete in the asset catalog, fast chat-filter prefix matching, and resolving shortened asset-name queries across millions of game items.
- #25mediumfoundational
25. Meeting Rooms II
Find the minimum number of rooms needed to hold all meetings without overlap — Roblox applies the same interval-scheduling logic to allocate game servers and physics simulation slots across concurrent player sessions.
- #26mediumfoundational
26. Game of Life
Simulate one generation of Conway's Game of Life on a 2D board using in-place state encoding — a direct parallel to how Roblox's voxel engine computes next-tick block states for physics simulations across large terrain grids.