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 8 problems of 25
- #1easyfoundational
1. Two Sum
Find two indices in an array whose values sum to a target — Confluent uses this to check hash-map intuition before moving to streaming-log questions.
- #2easyfoundational
2. Best Time to Buy and Sell Stock
Find the maximum profit from a single buy-sell over an array of daily prices — Confluent maps it to a single-pass min-tracker that mirrors how a Kafka consumer holds running aggregates per partition.
- #3easyfoundational
3. Single Number
Find the one element appearing once when every other appears twice — Confluent uses it to probe whether you know XOR tricks before scaling to deduplicating Kafka records.
- #4easyfoundational
4. Majority Element
Return the element appearing more than n/2 times — Confluent uses it to test Boyer-Moore voting, which maps cleanly to streaming heavy-hitters over a Kafka topic.
- #5easyfoundational
5. Contains Duplicate
Return true if any value appears at least twice — Confluent uses it to check if you reach for a Set immediately, the same instinct used to dedupe Kafka messages.
- #6easyfoundational
6. Valid Anagram
Decide if two strings are anagrams — Confluent uses it as a warm-up to test count-based hashing before moving to streaming-character-frequency questions.
- #7easyfoundational
7. Missing Number
Find the missing number in [0..n] — Confluent uses it to probe whether you reach for sum-formula or XOR before they extend to detecting missing offsets in a Kafka log.
- #8easyfoundational
8. Design HashMap
Implement a HashMap without using built-in map APIs — Confluent uses it to see if you understand bucket chaining, since Kafka's partition assignment is hash-based at heart.