The O(1) space constraint is what tripped me up at first.
Start by clarifying the problem and edge cases, then propose a single-pass solution using two pointers or counters to track the current streak and the maximum streak. Emphasize that this achieves O(n) time and O(1) space by only storing a few variables.
Pro tip: Mention that this is essentially a run-length encoding problem and that the same pattern applies to many streaming data scenarios, showing you can connect the problem to real-world systems at Netflix.
Ask about input format (e.g., array of strings or IDs), whether the array can be empty, and if there are multiple shows with the same streak. Confirm that 'streak' means consecutive identical elements.
Explain that you will iterate through the array once, maintaining a current streak count and a maximum streak count. When the current element matches the previous, increment the current streak; otherwise, reset it to 1.
Use a small example like ['A','A','B','B','B','A'] to demonstrate how the counters update and how the maximum is tracked. This shows your solution works and helps catch off-by-one errors.
State that the algorithm runs in O(n) time because it makes a single pass, and uses O(1) extra space since only a few variables are needed regardless of input size.
Discuss edge cases such as an empty array (return 0), a single-element array (return 1), and arrays where all elements are the same (return n).
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.