Palantir Coding Interview Questions
25 Palantir coding interview problems with full optimal solutions — 15 easy, 7 medium, 3 hard. Every problem ships with multiple approaches (brute-force first, then the optimal), complexity tables for each, company-specific tips on what an Palantir interviewer values, and a FAQ section.
Showing 3 problems of 25
- #19mediumsometimes asked
19. Kth Largest Element in an Array
Find the kth largest element in an unsorted array. Palantir asks this to test whether you reach for a min-heap of size k — the same streaming primitive their dashboards use to compute top-k entities by row count without scanning the whole dataset twice.
- #21mediumsometimes asked
21. Longest Increasing Subsequence
Given an integer array nums, return the length of the longest strictly increasing subsequence. Palantir asks this to see whether you know the O(n log n) patience-sort trick — they care because the same algorithm powers monotone trend extraction over a sorted-by-time partition in a Foundry transform.
- #22mediumsometimes asked
22. Critical Connections in a Network
Find all critical edges (bridges) in an undirected network whose removal disconnects it. Palantir asks this because their ontology team uses Tarjan's bridge algorithm to flag dependency edges in an ETL DAG whose removal would silo a downstream pipeline — bridges are blast-radius signals.