Palo Alto Networks·Software Engineer·Technical Phone Screen
Jul 2026
Palo Alto Networks SWE interview with a fairly meaty algorithmic question that required more than just coding. They wanted the full picture: data structures, complexity, edge cases, the works.
- Given two lists of strings, return all elements that appear in the first list but not the second, after normalizing both lists (e.g., lowercasing and trimming whitespace). Walk through your algorithm, data structure choices, duplicate handling, and time/space complexity.
“My first instinct was just to throw everything into a set and call it a day, but they kept pushing.” The rest of the author's notes on Software Engineer interview at Palo Alto Networks, Technical Phone Screen round, covers how they worked through the question, what the panel pushed back on, and what they would do differently.
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