Palo Alto Networks coding interview
questions, leaked.
26 problems reported across recent Palo Alto Networks interviews. Top patterns: array, string, hash table. The list below is what most reported candidates actually saw, plus the honest play if you can't grind all of it.
Palo Alto Networks interviews lean hard on arrays and strings. Of 26 reported problems, 15 are array-focused and 11 involve strings. You're looking at a 65% medium-difficulty surface, so expect problems like Longest Substring Without Repeating Characters, LRU Cache, and Sliding Window Maximum to show up. The good news: most of these follow recognizable patterns. The reality: you'll face at least one problem you haven't drilled. That's where StealthCoder steps in, running invisible during your live assessment and surfacing a working solution when you hit a wall.
Top problems at Palo Alto Networks
| # | Problem | Diff | Frequency | Pass % | Patterns |
|---|---|---|---|---|---|
| 01 | LRU Cache | MEDIUM | 100.0 | 45% | Hash Table · Linked List · Design |
| 02 | Find the Longest Equal Subarray | MEDIUM | 94.5 | 36% | Array · Hash Table · Binary Search |
| 03 | Longest Substring Without Repeating Characters | MEDIUM | 84.2 | 37% | Hash Table · String · Sliding Window |
| 04 | Median of Two Sorted Arrays | HARD | 76.5 | 44% | Array · Binary Search · Divide and Conquer |
| 05 | String Compression | MEDIUM | 76.5 | 58% | Two Pointers · String |
| 06 | Sliding Window Maximum | HARD | 64.9 | 48% | Array · Queue · Sliding Window |
| 07 | Maximum Length of a Concatenated String with Unique Characters | MEDIUM | 64.9 | 54% | Array · String · Backtracking |
| 08 | Meeting Rooms | EASY | 64.9 | 59% | Array · Sorting |
| 09 | Group Anagrams | MEDIUM | 64.9 | 71% | Array · Hash Table · String |
| 10 | Min Stack | MEDIUM | 64.9 | 56% | Stack · Design |
| 11 | Two Sum | EASY | 64.9 | 56% | Array · Hash Table |
| 12 | Insert Delete GetRandom O(1) | MEDIUM | 64.9 | 55% | Array · Hash Table · Math |
| 13 | Binary Tree Level Order Traversal | MEDIUM | 64.9 | 71% | Tree · Breadth-First Search · Binary Tree |
| 14 | Minimum Path Sum | MEDIUM | 64.9 | 66% | Array · Dynamic Programming · Matrix |
| 15 | Restore IP Addresses | MEDIUM | 55.7 | 53% | String · Backtracking |
| 16 | Search in Rotated Sorted Array | MEDIUM | 55.7 | 43% | Array · Binary Search |
| 17 | Basic Calculator | HARD | 55.7 | 46% | Math · String · Stack |
| 18 | Top K Frequent Words | MEDIUM | 55.7 | 59% | Array · Hash Table · String |
| 19 | Valid Parentheses | EASY | 55.7 | 42% | String · Stack |
| 20 | Design HashMap | EASY | 55.7 | 66% | Array · Hash Table · Linked List |
| 21 | Word Break | MEDIUM | 55.7 | 48% | Array · Hash Table · String |
| 22 | Merge Sorted Array | EASY | 55.7 | 53% | Array · Two Pointers · Sorting |
| 23 | Merge Two Sorted Lists | EASY | 55.7 | 67% | Linked List · Recursion |
| 24 | Integer to Roman | MEDIUM | 55.7 | 69% | Hash Table · Math · String |
| 25 | Shortest Path in Binary Matrix | MEDIUM | 55.7 | 50% | Array · Breadth-First Search · Matrix |
| 26 | Longest Palindromic Substring | MEDIUM | 55.7 | 36% | Two Pointers · String · Dynamic Programming |
Frequencies derived from public community-tagged interview reports. Click a row to view on LeetCode.
You have a week, maybe less. You can't out-grind the list above. StealthCoder runs invisibly during the actual Palo Alto Networks OA. The proctor cannot see it. Screen share cannot detect it. Built by a senior engineer who knows the OA is theater. This is the script.
Get StealthCoder- array15 · 58%
- string11 · 42%
- hash table10 · 38%
- design4 · 15%
- sorting4 · 15%
- binary search3 · 12%
- linked list3 · 12%
- sliding window3 · 12%
- math3 · 12%
- stack3 · 12%
Arrays dominate the question bank here, often paired with hash tables to catch candidates who can't optimize past brute force. Strings come in second, frequently tested alongside hash tables and sliding windows. The top problems cluster around two core patterns: hash-table lookups (Two Sum, Group Anagrams, Longest Substring Without Repeating Characters) and sliding-window subproblems (Find the Longest Equal Subarray, Sliding Window Maximum). If you're short on time, nail those two. Design problems (LRU Cache, Min Stack, Insert Delete GetRandom O(1)) demand hand-coding data structures; they're harder to fake. Median of Two Sorted Arrays and Sliding Window Maximum are the rare hard problems that separate stronger candidates. If you blank on edge cases or get stuck on optimization mid-interview, StealthCoder solves it in seconds without the proctor knowing.
Companies with similar patterns
If you prepped for Palo Alto Networks, these companies recycle ~60% of the same topics.
You've seen the list.
Now make sure you pass Palo Alto Networks.
Memorizing every problem above in a week is a fantasy. StealthCoder is the hedge: an AI overlay that's invisible during screen share. It reads the problem on screen and surfaces a working solution in under 2 seconds. Built by a senior engineer who knows the OA is theater. This is the script. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Palo Alto Networks interview FAQ
How many array problems should I solve before the interview?+
At least 8 to 10. Arrays make up 58% of the reported problems here. Focus on the ones in the top list: Two Sum, Group Anagrams, and Median of Two Sorted Arrays. You're not trying to solve all 15, just the high-leverage ones that teach you sorting, binary search, and hash-table pairing.
Is hash-table fluency essential for Palo Alto Networks?+
Yes. Hash tables appear in 10 problems, often paired with arrays and strings. They're the go-to optimization for problems like Two Sum, Longest Substring Without Repeating Characters, and Group Anagrams. You can't skip this topic without risking a brute-force solution mid-interview.
What should I drill first if I have one week?+
Sliding-window problems combined with hash tables. Longest Substring Without Repeating Characters and Find the Longest Equal Subarray are classics, and the pattern is reusable across the question bank. You'll see sliding-window thinking on at least 3 to 4 problems. Do those first, then tackle design problems like LRU Cache and Min Stack.
Are the hard problems worth my time?+
Only two hard problems show up in the top-reported list: Median of Two Sorted Arrays and Sliding Window Maximum. If you're strong on mediums, skip hard problems unless you're interviewing for a senior role. Most candidates who nail mediums pass the screen.
What's the hardest thing about Palo Alto Networks interviews?+
The design problems. LRU Cache, Min Stack, and Insert Delete GetRandom O(1) require you to code real data structures, not just find an optimal path. They're medium-difficulty by tag but tricky in practice. String and array problems have clearer patterns. Design problems reward depth, not just speed.