Watch the pattern move.
Use visual lessons to make pointer movement, windows, trees, graphs, and state changes concrete.
Visual DSA learning • Built for iPhone
Learn the pattern.
Explain the solution.
Cozytek Code helps you prepare for coding interviews by turning data structures and algorithms into reusable visual patterns—then guiding you from recognition to a clear solution outline.
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recognize the signal
reason → outline → code
The Cozytek method
Clear thinking leads to clear code.
Strong interview answers are more than working code. Cozytek Code teaches the reasoning that comes first: what the prompt is signaling, which invariant makes the approach safe, and how to communicate the plan before you type.
Recognize the signal.
Learn the words and constraints that point toward two pointers, BFS, dynamic programming, and more.
Name the invariant.
Understand why each move is valid, what stays true, and what work has been safely eliminated.
Shape the solution.
Turn the approach into a structured outline, code it, review edge cases, and explain the tradeoffs.
Start with a pattern
Learn what transfers across problems.
The goal is not to memorize one accepted answer. It is to understand the pattern well enough to recognize it in a new prompt, explain it clearly, and rebuild the solution with confidence.
Sequence pattern
Two pointers
Use ordered movement to remove impossible pairs and turn nested work into one pass.
READ LESSON →O(n) Contiguous rangeSliding window
Reuse the overlap between adjacent ranges instead of rebuilding every answer from scratch.
READ LESSON →O(n) Ordered searchBinary search
Use one comparison to discard half of a sorted or monotonic search space.
READ LESSON →O(log n) Graph traversalDFS vs. BFS
Choose a stack for deep exploration or a queue when distance should be earned evenly.
READ GUIDE →O(V+E) Complexity strategyBig-O analysis
Read loops, recursion, and helper storage as a cost story before code details distract you.
READ GUIDE →O(?) Curriculum mapDSA foundations
See how arrays, hash maps, trees, graphs, heaps, sorting, and strategy patterns fit together.
EXPLORE MAP →{ }Inside the app
Think. Practice. Build. Grow.
Move from visual understanding to interview-style practice, solution guides, mastery checks, custom questions, and spaced review—all in one focused learning loop.
PRACTICE / pattern library
BUILD / guided solutions
GROW / mastery tracking
WATCH / visual lessons
A growing curriculum
From arrays to dynamic programming.
Learn core data structures, common interview patterns, and the strategy skills that help you compare approaches and explain complexity.
Arrays, strings & hash mapsDirect access, scanning, frequency maps, sets, prefix information.
Two pointers & sliding windowOrdered movement, contiguous ranges, reusable overlap, one-pass invariants.
Binary search & sortingHalf-space elimination, monotonic answers, ordering, comparison tradeoffs.
Trees, graphs, DFS & BFSTraversal state, connected regions, frontiers, shortest unweighted paths.
Backtracking, heaps & greedyChoose-or-skip search, top-k state, local choices, pruning.
Dynamic programming & Big-OOverlapping subproblems, state transitions, time and space analysis.
“The interview is not only asking whether you can code it. It is asking whether your reasoning is clear enough to trust.”
Cozytek Code is designed to help you practice both parts.
Questions, answered
About Cozytek Code
What is Cozytek Code?
Cozytek Code: Interview Prep is an iPhone learning app for data structures, algorithms, and reusable coding interview patterns. It combines visual lessons, guided practice, solution outlines, mastery checks, and progress tracking.
Who is it for?
It is for learners preparing for technical coding interviews who want to understand why common patterns work—not only memorize solutions. It can support beginners building DSA foundations and experienced candidates refreshing interview reasoning.
Which topics does the app cover?
The curriculum includes arrays, strings, hash maps, two pointers, sliding window, binary search, trees, graphs, DFS, BFS, backtracking, heaps, greedy strategies, dynamic programming, sorting, and Big-O analysis.
Does it include practice problems?
Yes. The app includes a growing library of interview-style problems, solution guides, pattern-focused mastery checks, custom practice tools, progress metrics, and spaced-repetition review.
Where is progress stored?
Your attempts, time, mistakes, accuracy, streaks, and mastery state stay on your device and can sync privately through iCloud when available.
Is every feature free?
The app is free to download. Full curriculum and practice access is available through an optional premium subscription.
Your next pattern is waiting
Build coding skills that transfer across problems.
Download Cozytek Code on iPhone and start turning visual understanding into a confident interview explanation.