Arrays, Strings & Hashing

Palo Alto Networks interviews like a systems company. The array and string questions here sit at medium difficulty, but the round rarely stops at "does it pass the tests." The interviewer keeps pulling the problem back toward fundamentals. How does your hash function distribute keys? What happens when the table fills up? Why did you sort first? How would you do this without the loop you just reached for? The code opens the round. The conversation about how it works underneath decides it.

Three questions recur across candidate reports for backend and new-grad roles, and they map cleanly onto arrays, strings, and hashing. Partitioning an array into a Premium question shows up in a senior backend screen. A Premium question "without using a single loop" is the string curveball from the same loop. And "implement a hash table without any built-in map," followed by questions on rehashing and hash-function families, is the hashing round that most separates prepared candidates from the rest. All three appear below with the exact framing candidates were handed.