Data Structure Display vs Codelet
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Data Structure Display
Explore and learn data structures through dynamic debugging and visual observation of changes. This app covers linear structures, trees, graphs, and recursive algorithms like the Tower of Hanoi, offering interactive learning experiences.
- Dynamic data structure debugging
- Visual observation of data structure changes
- Learn linear structures (arrays, lists, queues, stacks)
- Explore tree structures (binary, AVL, red-black, heap)
- Understand graph structures and algorithms
- Debug recursive algorithms like Tower of Hanoi
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A novel data structure learning app, the most significant feature is that you can dynamically debug the data structure in this app, and visually observe the changes in the data structure during the operation. In this app you can learn the following data structures: 1. Linear structures, including arrays, linked lists, queues, stacks. Linear structures are the basis for other advanced data structures, as fine as advanced algorithms. 2. Tree structures, including binary tree, binary search tree, AVL tree, red-black tree, and heap. In this app, you can dynamically debug three traversals of the binary tree (including non-recursive traversal implementations), searching in the tree, balance adjustments in the AVL tree and red-black tree, and heap sorting. Give you the ability of handwritten red-black trees. 3. Graph structure, including the adjacency list storage representation of the graph structure, depth-first search and breadth-first search, finding the Euler path in the graph, topological sorting, maximum connected components, minimum spanning tree problem, and shortest single source Path problem. It also provides dynamic debugging of these classic graph algorithms. 4. The data structure introductory class will talk about the problem of the Tower of Hanoi. The algorithm that solves this problem is often recursive. This app provides dynamic debugging of the Tower of Hanoi problem, so you can no longer be confused about the recursive calls of the Tower of Hanoi.
Codelet
Prepare for technical interviews by identifying core coding patterns and analyzing your performance. Practice coding questions conveniently to improve your skills and pinpoint areas for growth.
- Identify core patterns
- Analyze approaches
- Track performance
- Identify improvement areas
- Practice coding questions
- Anytime, anywhere practice
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∙ Identify and analyze the core patterns and approaches ∙ View how well you’re doing and where you can improve ∙ Practice coding questions anywhere and anytime
Screenshots
Verdict
The clearest difference is in-app purchases: Codelet at none against Data Structure Display's 1. Codelet also leads on rating (4.7 vs 4.5) and update cadence (every 2 months vs every 5 months). Data Structure Display's advantage is ratings volume (676 vs 127) and review sentiment (62% vs 53%). On price, ads and iOS requirement there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. Data Structure Display sells 1 one-off in-app purchase. Codelet asks for nothing beyond the download.
Codelet holds the better App Store score, 4.7 against 4.5. That said, the two scores are not equally well evidenced: Data Structure Display has 676 ratings behind it against 127, so its average is the more settled of the two. Written reviews complicate that: 62% of Data Structure Display's written reviews are positive against 53% of Codelet's, so the app with the better star average is not the one people write more warmly about.
Data Structure Display ships an update every 5 months, Codelet every 2 months. The most recent releases landed on September 24, 2026 and August 13, 2026 respectively.
| Parameter | Data Structure Display | Codelet |
|---|---|---|
| Price | Free | Free |
| Rating | 4.5 (676 ratings) | 4.7 (127 ratings) — better |
| Positive reviews | 61.9% of reviews — better | 53.3% of reviews |
| Number of ratings | 676 — better | 127 |
| Update frequency | Every 5 months | Every 2 months — better |
| Ads | No | No |
| In-app purchases | Yes | No — better |
| Monetization | Free with in-app purchases | Free — better |
| Devices | iPhone, iPad, iPod, Mac — better | iPhone, iPod |
| Requires iOS | 13.0 — better | 13.4 |
| Further details — not scored | ||
| Size | 8 MB | 25 MB |
| Age rating | 4+ | 4+ |
| Developer | Jinan Matrix Information Technology Co., Ltd. | Codelet LLC |
Customer experience
Data Structure Display
Codelet
Bugs and requests
Data Structure Display
Reported bugs
2 issues- Aggressive review request frequency
- Inconsistent dark mode functionality between iOS and macOS
Requested features
4 requests- Dark mode implementation
- Comprehensive coverage of all data structure variants
- More practical exercises and problems
- Ad-supported free tier instead of paywall
Codelet
Not enough reviews yet to summarise bugs or requests.
In-app purchases
Data Structure Display
- Unlock all data structures$2.99
Codelet
No in-app purchases





