Felt like a warmup but I still fumbled the off-by-one explanation.
Start by defining binary search as an efficient algorithm for finding a target in a sorted array by repeatedly halving the search interval. Then walk through the step-by-step process, emphasizing the role of the midpoint and the conditions for adjusting the low and high pointers. Finally, discuss time and space complexity, and mention edge cases like empty arrays or duplicates.
Pro tip: At Google, interviewers value clarity and correctness: explicitly state the loop invariant (e.g., target is within [low, high]) and discuss potential pitfalls like integer overflow when computing mid, showing you think about robust code.
State that binary search requires a sorted array and a target value, and it returns the index of the target or -1 if not found.
Describe initializing low and high pointers, then iteratively computing the midpoint and comparing it to the target, adjusting low or high accordingly until the target is found or the search space is empty.
Mention that time complexity is O(log n) because the search space halves each iteration, and space complexity is O(1) for the iterative version.
Cover scenarios like empty array, target not present, duplicates (which may require finding first/last occurrence), and the importance of avoiding integer overflow when calculating mid.
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