Master the two pointers pattern for coding interviews: variants, Java examples, common mistakes, and a two-week practice plan to solve array problems in O(n).
Master the Topological Sort pattern: spot the hidden DAG, memorize the Kahn’s algorithm Java template, and get cycle detection free. 4 classic problems.
Learn the monotonic stack pattern to solve next-greater-element, daily temperatures, and largest-rectangle interview problems in O(n). Worked Java examples for 2026.