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 5 problems of 25
- #4hardsometimes asked
4. Median of Two Sorted Arrays
Glean tests this to verify that candidates can reduce a tricky problem to binary search on the partition point — the same reasoning behind efficiently finding the rank-based cutoff in a dual-index search system without merging both indexes.
- #23hardvery frequently asked
23. Merge K Sorted Lists
Merge K Sorted Lists is a cornerstone Glean interview problem — it directly models merging ranked result sets from K index shards into one ordered output stream, a core operation in any distributed search engine.
- #42hardsometimes asked
42. Trapping Rain Water
Glean asks this hard-tier problem to test whether candidates can derive an O(1)-space two-pointer solution from an O(n)-space prefix/suffix scan — the same optimization mindset that matters in large-scale index traversal where memory allocation is expensive.
- #127hardsometimes asked
127. Word Ladder
Glean uses Word Ladder to test BFS on an implicit graph — a critical skill when traversing semantic neighborhoods in a word-embedding space or computing edit-distance hops between query terms for query expansion.
- #642hardvery frequently asked
642. Design Search Autocomplete System
This is arguably the most Glean-relevant problem that exists — it asks you to build the autocomplete system that is Glean's core product differentiator, combining a Trie with a frequency-ranked top-K retrieval engine.