Databricks Coding Interview Questions
27 Databricks coding interview problems with full optimal solutions — 18 easy, 7 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 Databricks interviewer values, and a FAQ section.
Showing 7 problems of 27
- #19mediumfoundational
19. Top K Frequent Elements
Return the k most frequent integers — the canonical heap-vs-bucket-sort duel that Databricks maps directly to top-N analytics queries and the cardinality-estimation problems inside Delta Live Tables.
- #20mediumfoundational
20. Min Stack
Design a stack that retrieves its minimum in O(1) — Databricks uses this to test auxiliary-state discipline, a pattern that shows up when tracking minimum-cost DAG nodes in a query optimizer.
- #21mediumfoundational
21. Find Peak Element
Locate any local maximum in O(log n) — Databricks ties this to binary-search strategies for finding optimal partition-split points in Delta Lake's data-skipping index.
- #22mediumfoundational
22. Course Schedule
Detect a cycle in a directed prerequisite graph — the textbook DAG-validation problem that Databricks applies directly to detecting circular dependencies in Delta Live Tables pipeline DAGs.
- #23mediumfoundational
23. Partition Labels
Greedily partition a string so each character appears in exactly one part — a range-merging pattern Databricks reuses when computing non-overlapping file-range compaction windows in Delta Lake's OPTIMIZE command.
- #24mediumfoundational
24. Subarray Sum Equals K
Count contiguous subarrays whose values sum to k — the prefix-sum technique here is the same one Databricks uses to compute rolling aggregations over unbounded streaming windows in Structured Streaming.
- #25mediumfoundational
25. Number of Islands
Count connected land components in a 2-D grid — a BFS/DFS connected-components pattern Databricks extends to counting disconnected data-lake zones and partitioning graph-based cluster topology.
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