Confluent Coding Interview Questions
25 Confluent 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 Confluent interviewer values, and a FAQ section.
Showing 5 problems of 25
- #21hardfoundational
21. Find Median from Data Stream
Design a structure that absorbs numbers and reports the running median — Confluent uses it because two-heap streaming aggregates are the textbook fit for an online consumer over a Kafka topic.
- #22hardfoundational
22. LFU Cache
Design an O(1) get/put cache with least-frequently-used eviction — Confluent uses it because LFU + recency-within-frequency mirrors the partition-pinning logic in a sticky consumer assignor.
- #23hardfoundational
23. Smallest Range Covering Elements from K Lists
Find the smallest range [a, b] containing at least one element from each of k sorted lists — Confluent uses it because k-way merge is the same shape as joining k partitions in a Kafka topic.
- #24hardfoundational
24. The Skyline Problem
Compute the outline of a city skyline from rectangular buildings — Confluent uses it because event-sweep + max-heap aggregation maps onto windowed aggregations over a Kafka topic.
- #25hardfoundational
25. Next Greater Element IV
For each index find the second next greater element to the right — Confluent uses it because monotonic-stack chaining mirrors backpressure handling across two log positions inside a Kafka partition.