1582 articles
Design a class to track the kth largest element in a live data stream. Learn why a min-heap of exactly k elements is the perfect data structure, trace through a full dry run, avoid the classic pitfalls, and walk away with clean Python and JavaScript solutions ready for FAANG interviews.
Most shuffle implementations are silently biased. Learn why naive random fails, how Fisher-Yates guarantees every permutation is equally probable, and what FAANG interviewers really want to hear when they ask this question.
LeetCode 1480 is the gateway to one of the most powerful patterns in competitive programming and FAANG interviews: prefix sums. Master the in-place O(1) space solution, understand why the prefix sum array unlocks O(1) range queries, and learn the real follow-up questions — range sum queries, subarray sum equals K, and 2D matrix prefix sums — that interviewers ask once you solve this problem in thirty seconds.
Learn why 3Sum is a FAANG interview staple — how sorting enables two pointers, why deduplication trips up even strong candidates, a full visual dry run, and every common bug explained with Python and JavaScript solutions.
LeetCode 11 explained from scratch: why this is a greedy problem, the formal proof that you must always move the shorter pointer, a full step-by-step dry run, common traps, and clean Python + JavaScript solutions. Master the pointer-elimination pattern that appears throughout FAANG interviews.