What to actually use to prepare for a tech interview.

Teaches the twenty or so patterns that sit underneath almost every coding interview question, so you stop memorising solutions and start recognising problem shapes. Solve one sliding window problem here and you can solve the next forty on your own.

The layer below pattern practice: arrays, linked lists, stacks, queues, trees, heaps, graphs and hash tables, each built up from first principles with the complexity analysis that interviewers actually ask about. Start here if pattern courses feel like they are moving too fast.

The ordered path through coding interview preparation, from data structure fundamentals to patterns to company-specific practice. Use it when you have the material but no idea what to do first.

A preparation track aimed specifically at the large tech company loop, where the bar on problem difficulty, communication and time pressure is higher than most. It sets the standard you are being measured against before you walk in.

Dynamic programming broken into a handful of recognisable families such as knapsack, unbounded knapsack, longest common subsequence and palindromic subsequence, rather than presented as a bag of clever tricks. It is the topic most candidates give up on, which is exactly why learning it pays.

Seventy five questions chosen for coverage rather than volume, each mapped back to the pattern it belongs to. This is the list to work when you have four weeks and cannot afford to wander.

Walks through classic object oriented design problems such as a parking lot, a library system and a card game, showing how to go from a vague prompt to class diagrams and working interfaces. Covers the round that candidates most often prepare for last and fail first.

Builds a bank of structured stories from your own experience and teaches you to deliver them without rambling. The behavioural round decides more offers than engineers expect, and it is the cheapest round to get good at.

Complexity analysis explained properly, including the amortised and space cases that trip people up under pressure. Short, and it removes a category of interview mistake entirely.

Graph traversal, shortest paths, topological ordering, union find and the problems that hide a graph inside a grid or a list of dependencies. Recognising the graph is usually harder than traversing it.

The tree patterns that carry most tree questions: level order traversal, root to leaf paths, depth first accumulation and binary search tree invariants. Trees appear in almost every loop, so the return on two focused weeks is high.

Recursion taught as a technique you can trust rather than one you hope works, covering base cases, the call stack, backtracking and the conversion to iteration. It is the prerequisite for trees, graphs and dynamic programming all at once.

Threads, locks, condition variables, deadlock and the classic synchronisation problems that senior loops use as a filter. Fewer candidates prepare for this round, which makes preparing for it unusually valuable.

A browsable practice library organised by pattern and by data structure rather than by an arbitrary difficulty number, so you can drill exactly the weakness you found this week. Filterable by company as well.

The well known seventy five problem list, presented with the pattern each question belongs to instead of as a bare checklist. Free, and a reasonable place to test whether your preparation is actually working.

Per company breakdowns of the loop structure, the rounds you will face and what each one is scoring, for the major technology employers. Read the guide for your target company in the week before the loop, not the night before.

Joins, aggregation, window functions and the query patterns that data and backend interviews return to again and again. If your role touches a database, this round is on your loop whether you expected it or not.

The multi month self study plan one engineer used to go from web developer to a large technology company, published as a checklist covering the whole computer science foundation. Enormous, free, and honest about how long it takes.

Tell it how many weeks you have and how many hours a week, and it generates an ordered problem list that fits. The successor to the Blind 75, and it removes the planning problem entirely.

Animated visualisations of data structures and algorithms that you step through with your own input, covering sorting, trees, graphs, heaps and more. For anything you can follow in code but cannot picture.

Princeton's algorithms course, free to audit, covering union find, sorting, priority queues, search trees and hash tables with real analysis and demanding programming assignments. A proper course rather than interview coaching.

Free peer mock interviews where you interview someone else and then they interview you, with the question and solution supplied to each interviewer. The price is the strongest argument for it.

One page with the time and space complexity of every common data structure operation and sorting algorithm, colour coded so the expensive cases are obvious. The single most reused reference in interview preparation.

A free dependency graph of coding interview topics, showing which subjects unlock which and giving each one a small problem set. It answers what to study next better than any list, and costs nothing.