Divide and conquer sorted data in O(log n) — the foundational search technique for sorted arrays, ranges, and answer spaces.
Five passes over the same idea, each from a different angle. Do them in order, or jump to whichever you need.
Binary search halves the search space at each step by comparing the target with the midpoint. Beyond simple array search, binary search applies to answer-space problems (binary search on answer), rotated arrays, peak finding, and lower/upper bound queries. It is a building block for more complex algorithms.
