1582 articles
LeetCode 35 — find the index where a target exists or should be inserted in a sorted array. The canonical FAANG left-boundary binary search and the from-scratch implementation of bisect_left.
Compute the integer square root (floor) of x using right-boundary binary search. Find the largest k where k*k <= x, understand the upper-mid trick, and learn why this is the mirror image of the left-boundary template.
LC 34 asks for the start and end index of a target in a sorted array. Solve it in O(log n) by running two separate binary searches — one for the left boundary and one for the right boundary. A top FAANG pattern.
Search a rotated sorted array in O(log n) by identifying which half is always sorted at each step and checking whether the target falls inside it. A top FAANG interview problem.
Find the minimum element in a rotated sorted array in O(log n) by comparing mid to hi to decide which side of the rotation pivot you are on. A classic FAANG pivot-search pattern.