HP Coding Interview Questions
25 HP 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 HP interviewer values, and a FAQ section.
Showing 9 problems of 25
- #1easyvery frequently asked
1. Two Sum
HP's firmware and driver teams frequently use look-up tables for O(1) dispatch — Two Sum tests whether you instinctively reach for a hash map instead of a brute-force scan, which matters when your code runs on embedded microcontrollers with tight loop budgets.
- #4hardoccasionally asked
4. Median of Two Sorted Arrays
HP's quality assurance and performance benchmarking tools compute statistical medians over sorted measurement arrays from multiple test runs or device sources. Achieving O(log(m+n)) time rather than O(m+n) requires binary search across array boundaries — a technique HP senior engineers are expected to command.
- #9easyoccasionally asked
9. Palindrome Number
HP firmware and driver code handles numeric identifiers for device serial numbers, cartridge IDs, and page counters. Palindrome Number tests digit-manipulation skills without string conversion — a meaningful constraint in embedded C where string allocation is expensive.
- #23hardoccasionally asked
23. Merge K Sorted Lists
HP's enterprise print-management servers merge sorted job queues from thousands of network printers into a single priority-ordered dispatch stream. Merge K Sorted Lists tests exactly this pattern — combining multiple sorted streams efficiently using a min-heap or divide-and-conquer, skills that matter in HP's large-scale IT infrastructure.
- #42hardoccasionally asked
42. Trapping Rain Water
HP's physical simulation software for environmental testing — used in product durability labs — models fluid accumulation on irregular surfaces. Trapping Rain Water is the algorithmic abstraction of this problem. HP engineers encounter it in the context of dynamic programming, two-pointer optimization, and reasoning about monotonic stack patterns.
- #51hardoccasionally asked
51. N-Queens
HP's enterprise scheduling and resource-allocation systems assign non-conflicting resources across dimensions — analogous to placing non-attacking queens on a chessboard. N-Queens is the canonical constraint-satisfaction problem HP uses to test backtracking discipline and pruning intuition in candidates for algorithm-heavy roles.
- #54mediumoccasionally asked
54. Spiral Matrix
HP's scanning and imaging pipelines traverse pixel data in structured patterns — raster scans, zigzag patterns, and spiral reads appear in color-calibration and print-head alignment routines. Spiral Matrix tests whether you can maintain boundaries and direction state without off-by-one errors, a critical skill for HP systems engineers.
- #127hardoccasionally asked
127. Word Ladder
HP's network diagnostics and configuration management tools find shortest transition paths between device states — analogous to Word Ladder's shortest transformation sequence. HP uses this problem to test BFS shortest-path reasoning, graph construction from implicit adjacency, and the ability to prune search space efficiently.
- #139mediumoccasionally asked
139. Word Break
HP's natural-language processing tools for document scanning and search decompose recognized text sequences into valid dictionary words — essentially the Word Break problem. HP uses it to assess dynamic programming depth and the ability to recognize overlapping subproblems in string segmentation.