1582 articles
Find the h-index from a sorted citations array in O(log n) time using left-boundary binary search. Full FAANG interview breakdown with visual dry run, all edge cases, and intuition behind the search condition.
Count spell-potion pairs where spell * potion >= success by sorting potions and binary searching for each spell threshold. Full FAANG-level breakdown with visual dry run, all edge cases, and ceiling division intuition.
LC 378 asks for the kth smallest element in an n x n matrix sorted row-by-row and column-by-column. Binary search on the value range [min, max] and count elements <= mid using a staircase walk. O(n log(max-min)) total.
LC 1552 asks you to place m balls in sorted basket positions to maximize the minimum distance between any two balls. Binary search on the minimum distance and greedily place balls to check feasibility. A classic maximize-minimum binary search pattern.
LC 154 extends the rotated minimum search to arrays with duplicates. When nums[mid] == nums[hi], neither half can be ruled out — safely shrink by decrementing hi. Worst case degrades to O(n). A hard variant that tests invariant reasoning.