Role Pack · Junior to Mid
DSA Patterns Pack
The 14 coding patterns that cover most interview problems, with templates and walkthroughs.
Sliding window, two pointers, BFS/DFS, DP, graphs, heaps and more, each with a template and a walkthrough.
- Questions
- 360
- Topics
- 20
- Pages
- 266pages
- 360 questions, every one with a model answer
- 14 pattern templates
- Complexity cheat sheet
- Pattern-to-problem mapping
- Timed practice sets
Get the DSA Patterns Pack — $9
One-off. Delivered as a PDF by email the moment payment clears.
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What is inside
20 chapters, in the order the interviews tend to ask them:
- Complexity analysis and interview communication
- Two pointers on sorted and partitioned data
- Sliding window on fixed and variable ranges
- Windows over streams and online inputs
- Fast and slow pointers for cycles and links
- Prefix sums and difference arrays
- Intervals, merging and sweep lines
- Stacks and the monotonic stack pattern
- Hash maps, counting and frequency analysis
- Heaps and priority queues
- Binary trees and their traversals
- Binary search and its boundary variants
- Binary search on the answer and monotone predicates
- Breadth first, depth first and weighted graph search
- Topological sort and dependency ordering
- Union find and disjoint set structures
- Backtracking and state exploration
- Dynamic programming foundations and patterns
- Greedy algorithms and exchange arguments
- Tries and prefix based problems
How the answers are built
Each chapter opens with the checklist the question is really testing. A few from this pack:
- State the bound after the argument, not before, and name the operation that dominates the total work.
- Two pointers only pay off when moving one index in one direction cannot make a valid answer unreachable.
- A fixed window moves by exactly one step each iteration, while a variable window grows until valid and shrinks until invalid again.
- A true stream forbids a second pass, so any technique that re-reads earlier items is unavailable by definition.
- The tortoise visits indices 0, 2, 4 and the hare 0, 1, 2, so inside a cycle they must collide within one lap.
- With prefix sums, the sum from index a to b is prefix at b plus one minus prefix at a, so every range query is O(1).
Questions this pack covers
- How do you state time complexity for an algorithm in an interview
- What actually counts towards the space complexity of a recursive call
- When is the two pointer technique valid on an unsorted array
- How do you prove the two pointer invariant is never broken
- What decides whether your window size is fixed or variable
- How do you prove the window invariant shrinks monotonically
- How do you compute a rolling median on an unbounded stream
- What data structure maintains a sliding maximum in amortised linear time
Each one is answered in full in the pack, with the reasoning written out rather than a bullet list.
About this pack
- How many questions?
- 360, spread across 20 topics, written out in full across 266 pages.
- Do the answers just list keywords?
- No. Each answer is written as prose, because that is what you have to reproduce when someone asks you the question.
- How do I get it?
- Pay once and the PDF arrives by email immediately, with a signed download link.
- Can I get it refunded?
- Yes, if it is not what you expected. See the refund policy.
