Data Structures & Algorithms
Everything for the coding round: the theory, the patterns that map a problem to a technique, a practice checklist to track progress, and worked solutions with multiple approaches.
Algorithms & Big-OComplexity notation, searching and sorting algorithms, recursion, and classic algorithm problems.Data StructuresArrays, objects, stacks, queues, linked lists, hash tables, trees and graphs — with JavaScript implementations.PatternsTwo dozen recurring patterns — the trigger that tells you which applies, the approach, complexity and reference code.Interview Core198 high-frequency interview problems grouped by pattern — the list to do first when time is short.Practice Checklist447 problems across 15 topics. Tick them off as you solve — progress saved in your browser.Worked Solutions397 problems solved with 468 approaches — brute force first, then optimal, with idea, complexity and code.