The Last Algorithms Course You'll Need vs Complete Intro to React v9

Across roughly nine hours and 60 lessons the course covers Big O time and space complexity, arrays, linked lists, queues and stacks, a ring buffer, recursion, the classic searches and sorts (linear, binary, bubble, quick), trees with BFS and DFS, heaps, maps, graphs with adjacency lists and matrices, and Dijkstra's shortest path. Reviewers repeatedly call it content-dense and "not the typical watered down content you find often on online courses." The honest mark-down is that it is implementation-first and fast — it condenses a full-semester CS course into under ten hours, so it favours breadth and live coding over slow, proof-heavy depth.

ThePrimeagen is the reason this course is so widely recommended. Reviewers describe his explanations as "full of joy and charisma," call him "an excellent communicator" who is "both down-to-earth and incredibly skilled and intelligent," and note that "you won't get bored and fall asleep." He implements most algorithms live rather than showing finished code, which learners consistently single out as the high point. This is one of the most engaging instructors in the DSA space and it shows in the 4.9/5 rating.

The course is completely free — all you need is a free Frontend Masters account — yet it sits behind, and is the same quality as, Frontend Masters' paid catalogue. For roughly nine hours of well-produced video plus a bespoke practice tool, reviewers call it "a worthy investment" and say "there is no other algorithm course that can teach you so many topics in such an efficient way." The only caveat on value is the subscription framing: the deeper Part 2 (advanced algorithms) sits behind a paid Frontend Masters subscription.

The standout practical feature is the kata-machine, a bespoke GitHub repository ThePrimeagen wrote that generates a fresh daily set of algorithm exercises with a ready testing environment, so you implement each structure from scratch in TypeScript rather than just watching. Learners praise this as the thing that makes the knowledge stick. The caveat is that there is no graded capstone or certificate, and some implementations (notably the doubly linked list) are "complicated, or rather convoluted, to implement," which can stall practice.

The stated goal is to teach enough DSA that, after practice, you could pass interviews at a large tech company, and reviewers report it delivered exactly that mental model — one four-year professional said "this was exactly what I needed to get back on track." The patterns (Big O reasoning, BFS/DFS, Dijkstra, the common sorts) are the bread and butter of coding interviews. But it is a foundation, not a credential: there is no certificate, and complete beginners will need significant outside practice before the interview goal is realistic.

v9 covers React 18 and 19 features (form actions, Suspense, the React Compiler) plus a modern Vite + TanStack Router + TanStack Query stack. Praised for currency, with a minority of long-term Frontend Masters subscribers flagging that other courses in the catalog can drift.

Brian Holt is the most consistently praised aspect across nine years of Hacker News mentions. Learners use words like 'excellent', 'great', and 'brilliant'. His pet adoption project framing is repeatedly cited as memorable.

Requires a Frontend Masters subscription (currently $39/month), which is consistently described as worth it if you complete more than one course per month. Less competitive against free alternatives if you only want a single React intro.

The single build-along project (an e-commerce app in v9, evolved from the pet adoption app of earlier versions) is praised for being non-trivial and integrating real ecosystem tools (TanStack Query, Vitest) rather than toy examples.

Holt spends real time on tooling (Vite, ESLint, Prettier, code-splitting, Vitest) and modern ecosystem choices, which is the single most-cited reason people say his courses transferred well to their day jobs.