1582 articles
Most candidates jump straight to sorting. Learn the O(n) one-pass trick that finds the minimum and maximum of the violated region, expands the boundary correctly, and handles all edge cases — plus every FAANG follow-up interviewers actually ask.
Master LeetCode 795 using the elegant count(max <= R) - count(max <= L-1) subtraction trick — a powerful O(n) pattern that unlocks a whole family of subarray counting problems asked at Amazon, Google, and Meta.
LC 992 is one of the cleanest examples of a non-obvious reduction in competitive programming. Learn the "exactly K = atMost(K) minus atMost(K-1)" insight, trace through a full visual dry run, and understand how this single pattern unlocks five related hard problems in one shot.
LeetCode 1007 seems deceptively simple but hides a key insight that trips up most candidates: only the value on the very first domino can ever unify an entire row. Learn why this candidate-reduction observation collapses six potential targets into at most two, how to count rotations efficiently in a single pass, and what FAANG interviewers ask as follow-ups — including generalization to N faces and streaming domino inputs.
Master LC 936 Stamping the Sequence with reverse greedy simulation. Learn the core insight that working backwards transforms an impossible forward search into a tractable greedy problem. Python and JavaScript solutions with full commentary.