Riot Games Coding Interview Questions
25 Riot Games coding interview problems with full optimal solutions — 13 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 Riot Games interviewer values, and a FAQ section.
Showing 9 problems of 25
- #14mediumfoundational
14. LRU Cache
Design a cache that evicts the least-recently-used key when capacity is hit — Riot's matchmaking and asset-streaming systems both lean on LRU eviction.
- #15mediumfoundational
15. Number of Islands
Count connected components of land on a 2D grid — Riot uses the same flood-fill structure for map-region partitioning and minimap pathfinding.
- #16mediumfoundational
16. Course Schedule
Detect whether a set of prerequisite pairs forms a valid DAG — Riot evaluates topological reasoning to model champion-ability dependency graphs and rune unlocks.
- #17mediumfoundational
17. Kth Largest Element in an Array
Return the kth largest element in an unsorted array — Riot tests this pattern when reasoning about leaderboard top-k queries and Elo bucket cutoffs.
- #18mediumfoundational
18. Coin Change
Find the fewest coins that sum to a target amount — Riot uses this DP pattern for RP-shop bundling and rune-page cost optimization.
- #19mediumfoundational
19. Top K Frequent Elements
Return the k most frequent elements in an array — a Riot favorite for telemetry-rollup and anti-cheat anomaly detection pipelines.
- #20mediumfoundational
20. Subarray Sum Equals K
Count contiguous subarrays whose sum equals k — Riot reaches for prefix-sum tricks when scanning telemetry streams for suspicious damage-windows.
- #21mediumfoundational
21. Daily Temperatures
For each day, find how many days until a warmer temperature — Riot uses the monotonic stack pattern when reasoning about next-event-time queries on server tick logs.
- #22mediumfoundational
22. Rotting Oranges
Compute the minutes until every fresh orange rots given multi-source spread — Riot tests multi-source BFS to reason about ability radii expanding over server ticks.