Not the string version you always prep for, which threw me off for a second.
First, clarify the problem definition: confirm whether 'longest common prefix' refers to the longest sequence of elements that appear at the beginning of both arrays in the same order. Then, propose an efficient algorithm that compares elements from the start until a mismatch is found, and discuss time and space complexity.
Pro tip: At Amazon, interviewers value candidates who proactively consider edge cases and scalability. Mention how your solution handles large arrays and whether it can be optimized for early termination.
Ask the interviewer to confirm the definition: is it the longest sequence of elements that are identical and appear at the start of both arrays? Also clarify if the arrays can be empty or have different lengths.
Start with a simple brute force: compare elements one by one until a mismatch. Then, note that this is already optimal for this problem, as you must examine each element until the first difference.
State that the time complexity is O(min(n, m)) where n and m are the lengths of the arrays, and space complexity is O(1) if you only return the length or O(k) if you return the prefix array, where k is the length of the prefix.
Discuss edge cases: empty arrays, arrays with no common prefix, one array being a prefix of the other, and arrays of different lengths.
Implement the solution in a clean, readable manner, and walk through a few test cases to verify correctness.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.