9 articles
Master Segment Trees and Binary Indexed Trees for FAANG interviews: range sum, min, max queries, point updates, lazy propagation, 2D BIT, and full problem index with complexity reference.
LC 307 Range Sum Query Mutable is the canonical benchmark for range query data structures. BIT solves it in O(log n) per operation; Segment Tree generalizes to any associative query. Master both before your next FAANG interview.
Count smaller elements to the right of every index using a Binary Indexed Tree (Fenwick Tree) with coordinate compression. The cleanest O(n log n) solution every interviewer expects.
Count pairs (i, j) with i less than j and nums[i] greater than twice nums[j]. The classic Hard problem for modified merge sort and BIT counting — the two techniques every senior interviewer expects.
Design a calendar that rejects double bookings. The classic interval-overlap interview problem solved with sorted maps in O(log n) per booking — the foundation for every range scheduling system.
Track range coverage with addRange, removeRange, and queryRange. Maintain disjoint intervals in a sorted map for amortized O(log n) — the canonical interview problem for interval merging logic.
Track the tallest stack height as squares fall onto a number line. The textbook problem for segment trees with lazy propagation, range max queries, and range-assign updates.
Count subarray sums in [lower, upper] using merge sort or Fenwick tree on prefix sums. The flagship Hard problem connecting prefix sums, divide-and-conquer counting, and BIT range queries.
Count all longest increasing subsequences with DP in O(n^2) or with a segment tree on values for O(n log n). The classic crossover problem between DP and range-query data structures.