Greatester Catch - Master Data Structures & Algorithms with Interactive Visualizations

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Zero Prerequisites

20 Free
Practice Quizzes

• No account setup required
• Instant feedback on answers
• Valid for 14 days after download

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200% Points
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• Triple points on first week
• Unlock achievements 3x faster
• Minimum 3 lessons completion

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Daily Challenges

50 Visualizer
Credits

• Access all sorting algorithms
• Unlimited replays for 30 days
• Works on Bubble, Quick, Merge, Heap Sort

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All bonuses valid for new users only. Points boost requires minimum 3 completed lessons. Visualizer credits expire 30 days after activation. Download and redeem within validity period.

Under the Hood

Greatester Catch transforms abstract computer science concepts into visual, interactive experiences. The algorithm visualizer renders sorting operations in real-time: watch Bubble Sort compare adjacent elements and swap them when needed, see Quick Sort partition arrays around pivot points, observe Merge Sort divide and conquer strategies step-by-step. Each operation displays Big O complexity notation with live step counters showing exactly how many comparisons and swaps occur.

The lesson system progresses through 40+ structured modules covering Variables & Data Types (15 min), Control Flow (20 min), Functions & Closures (25 min), Arrays & Lists (30 min), Linked Lists (35 min), Stacks & Queues (25 min), Hash Tables (35 min), Binary Trees, and Graph Traversal algorithms including BFS, DFS, and Dijkstra's shortest path. Every lesson includes complexity analysis breakdowns and real-world application scenarios where that data structure solves actual engineering problems.

The gamification engine tracks your progress through a points system: complete lessons to earn base points, pass quizzes for bonus multipliers, maintain daily streaks for consistency rewards. Achievement badges unlock at specific milestones: First Steps (complete first lesson), Bookworm (finish 10 lessons), Quiz Master (pass 25 quizzes), On Fire (7-day streak), Century (100 total points), Champion (complete all modules). Weekly contests pit your quiz speed and accuracy against global learners on a live leaderboard.

Verified Specifications

Developer

Olena Shcheblykina

What You Get

Complete DSA learning toolkit in one lightweight app

Interactive Algorithm Visualizer

Watch Bubble Sort, Quick Sort, Merge Sort, and Heap Sort execute step-by-step with color-coded element tracking. See Binary Search halve the search space with each iteration. Real-time status updates explain every comparison, swap, and partition operation.

Comprehensive Lesson Catalog

40+ structured lessons from Variables & Control Flow basics to advanced Graph Traversal algorithms. Each lesson includes time estimates (15-40 minutes), difficulty ratings (Easy/Medium/Hard), complexity analysis breakdowns, and real-world application examples.

Curated Quiz System

Test knowledge with multiple-choice questions featuring instant feedback. Receive detailed explanations for correct answers like "Binary search divides the search space in half each iteration." Track completion rate with visual progress indicators showing X/8 quizzes passed.

Daily Challenges & Weekly Contests

Build consistency with Daily Challenge badges that appear in orange-yellow gradients with flame icons. Compete globally in Weekly Contests testing quiz speed and accuracy. Maintain learning streaks tracked with fire emojis in your profile stats grid.

Gamified Progress Tracking

Earn points for completed lessons and passed quizzes displayed in white stat cards. Level up from Student (Level 1) with gold star badges. Unlock six achievements: First Steps, Bookworm, Quiz Master, On Fire, Century, Champion with circular badge indicators.

Quick Access Topic Navigation

Jump directly to Sorting (pink-magenta gradient icon), Searching (cyan-blue magnifying glass), Graphs (green-teal connected nodes), or Trees (orange branch structure) from the home dashboard. Rounded rectangle cards with right-pointing chevrons for instant section access.

How It Works

Learning Progression System

1

Filter by category: Browse lessons marked as Basics, Data Structures, or Algorithms using pill-shaped filter tabs at the top of the Lessons screen
2

Select lesson difficulty: Each card displays time commitment (15-40 minutes) and complexity level (Easy/Medium/Hard) with clock and bar chart icons
3

Study with context: Read structured explanations with Big O notation breakdowns and real-world use cases like "when to use hash tables for constant-time lookups"
4

Bookmark progress: Tap the bookmark icon to save lessons for later review and continue from where you left off at any chapter

Visualization & Practice Flow

1

Run algorithm simulations: Navigate to the Algo tab, select sorting method, press Run/Stop buttons with gradient backgrounds to control execution speed
2

Watch element interactions: Pink and gray bars highlight which array elements are being compared right now with status text like "Comparing 64 and 22 → Swap!"
3

Take timed quizzes: Answer multiple-choice questions about time complexity (O(n), O(log n), O(n²), O(1)) with radio button selection and green-bordered correct answers
4

Monitor stats dashboard: Check Profile tab for Day Streak counter, Total Points accumulated, Lessons Done count, and Quizzes Passed metrics in 2x2 grid layout

About the Developer

Developed by Olena Shcheblykina, Greatester Catch delivers computer science education through interactive visualizations optimized specifically for iPhone displays. The app requires iOS 16.6 or later and consumes only 5.9 MB of storage space.

Designed for students, bootcamp participants, and self-taught programmers preparing for technical interviews. Available exclusively on iPhone in English with a 4+ age rating and completely free with no in-app purchase requirements.

Start Mastering Algorithms Today

Join thousands of developers learning Data Structures & Algorithms through interactive visualizations. Download now and unlock your first achievement within 10 minutes.

Download Greatester Catch Free

40+

Structured Lessons

6

Achievement Badges

5.9MB

Lightweight Install

Master Data Structures & Algorithms