Glean Coding Interview Questions
25 Glean 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 Glean interviewer values, and a FAQ section.
Showing 8 problems of 25
- #1easyvery frequently asked
1. Two Sum
Glean uses this as a warm-up to test whether candidates think in hash maps first — the same O(1) lookup pattern that powers their inverted-index search engine at the core.
- #20easyfrequently asked
20. Valid Parentheses
Glean uses this to test stack intuition — the same mechanism that powers balanced-query parsing in enterprise search engines where unclosed brackets in a structured query must be caught before execution.
- #21easyfrequently asked
21. Merge Two Sorted Lists
Glean tests this as a gateway to Merge K Sorted Lists — a core primitive in multi-shard search result merging where ranked result sets from different index shards must be combined in order.
- #53easyfrequently asked
53. Maximum Subarray
Glean asks this to test Kadane's algorithm — a greedy scan that mirrors how a search ranker maximizes relevance score over a contiguous window of query tokens.
- #70easysometimes asked
70. Climbing Stairs
Glean uses this to probe dynamic programming intuition — recognizing that the answer is just Fibonacci reveals whether a candidate spots optimal substructure without prompting, a skill that translates directly to ranking-function design.
- #121easyfrequently asked
121. Best Time to Buy and Sell Stock
Glean screens for greedy and sliding-window reasoning here — the same mindset used when scanning a time-series of document relevance scores to find the best retrieval window.
- #206easyfrequently asked
206. Reverse Linked List
Glean tests pointer manipulation fundamentals here — the same in-place rewiring skill that matters when you're rearranging result-list nodes in a search ranking pipeline without allocating new memory.
- #217easysometimes asked
217. Contains Duplicate
Glean uses this as a fast filter to test whether candidates reach for a set before a nested loop — the exact reasoning behind deduplication in search indexing pipelines.