Sliding window is the move here but I initially started thinking about it as a brute force scan and wasted a couple minutes before course-correcting.
Clarify the problem and edge cases, then propose a sliding window solution that tracks the longest subarray with at most one zero. Explain how flipping the zero in that window yields the maximum contiguous ones, and analyze time and space complexity.
Pro tip: Mention that the problem is equivalent to finding the longest subarray with at most one zero, and that the same sliding window pattern can be extended to at most K zeros. This shows you recognize the underlying pattern and can generalize.
Confirm the input is a binary array (0s and 1s) and that flipping exactly one 0 is required. Ask about edge cases: all 1s, all 0s, empty array, and whether multiple valid answers exist.
Recognize that flipping a 0 to 1 is equivalent to finding the longest contiguous subarray that contains at most one 0. The answer is the index of that 0 (or any 0 if the array is all 1s).
Use a sliding window with two pointers (left and right) and a count of zeros in the current window. Expand right, and when zeros exceed 1, shrink left until zeros ≤ 1. Track the maximum window length and the index of the zero within it.
If the array contains no zeros, return -1 or any index (clarify with interviewer). If the array is all zeros, flipping any zero gives a sequence of length 1, so return 0 (or any index).
State that the time complexity is O(n) and space is O(1). Walk through a small example (e.g., [1,0,1,1,0,1]) to verify the algorithm and ensure the returned index is correct.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.