About
DSA Grind is a pattern-first reference for data structures and algorithms interviews, written in Java. 205 pages: 32 pattern guides and 153worked problem walkthroughs across 22 patterns.
The idea
Most problems are one of a small number of shapes. If you can name the shape, you already know the loop — what changes between problems is a couple of decisions inside it. So every pattern guide here opens with the skeleton for that pattern and names the knobs you turn, instead of asking you to re-derive the loop under time pressure.
Each problem page then does the same thing the same way: the statement, the algorithm in pseudocode, why it works, an ASCII trace on a small input, the Java solution, and the complexity. Reading the tenth one is fast because it is laid out like the first.
How to use it
- Read the roadmap once to see the shape of the whole thing.
- Work the patterns in order. Section 00 is assumed by everything after it.
- Before an interview, the template cheat sheet puts every skeleton on one page.
- Use all problems when you want to drill by difficulty, orsearch when you remember a problem but not where it lives.
Progress
Marking a page as read stores it in this browser, on this device, and nowhere else. There is no account, no sign-in and no server to send it to — the whole site is static HTML. Clearing your browser storage clears your progress, and it will not follow you to another device.
Language and conventions
Java throughout. ArrayDeque rather than Stack,ArrayDeque rather than LinkedList for queues, and the reasoning for those choices spelled out where it matters — that reasoning is often the actual interview question.
Corrections
These are study notes, offered as-is. If something is wrong it is wrong in the source notes too; every page footer shows which file it came from.