NBack for iPad vs Data Structure Display
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
NBack for iPad
This application offers a cognitive training tool designed to enhance working memory and mental acuity. It utilizes the N-Back task, a scientifically recognized method for improving cognitive abilities. Users can train their memory through various levels of difficulty.
- Working memory training
- N-Back task implementation
- Multiple difficulty levels (1'Back to 10'Back)
- Cognitive ability enhancement
- iPad optimized
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Stimulus => Sensory Memory => Working Memory => Long-Term Memory If you want to sharpen your mental ability, you should train your working memory. Train your working memory with 'NBack'. *NBack:The current answer matches the one from N steps earlier in the sequence. 1'Back --- 10'Back
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.
Screenshots
Verdict
The clearest difference is price: Data Structure Display at Free against NBack for iPad's $2.99. Data Structure Display also leads on ratings volume (676 vs 1) and update cadence (every 5 months vs every 12 months). NBack for iPad's advantage is rating (5.0 vs 4.5) and in-app purchases (none vs 1). On ads 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
Data Structure Display is free to download; NBack for iPad costs $2.99 up front. Data Structure Display sells 1 one-off in-app purchase. NBack for iPad asks for nothing beyond the download.
NBack for iPad holds the better App Store score, 5.0 against 4.5. That said, the two scores are not equally well evidenced: Data Structure Display has 676 ratings behind it against 1, so its average is the more settled of the two. Written reviews complicate that: 50% of NBack for iPad's written reviews are positive against 62% of Data Structure Display's, so the app with the better star average is not the one people write more warmly about.
NBack for iPad ships an update every 12 months, Data Structure Display every 5 months. The most recent releases landed on September 16, 2026 and September 24, 2026 respectively.
| Parameter | NBack for iPad | Data Structure Display |
|---|---|---|
| Price | $2.99 | Free — better |
| Rating | 5.0 (1 ratings) — better | 4.5 (676 ratings) |
| Positive reviews | 50.0% of reviews | 61.9% of reviews — better |
| Number of ratings | 1 | 676 — better |
| Update frequency | Every 12 months | Every 5 months — better |
| Ads | No | No |
| In-app purchases | No — better | Yes |
| Monetization | Paid | Free with in-app purchases — better |
| Devices | iPad | iPhone, iPad, iPod, Mac — better |
| Requires iOS | 18.2 | 13.0 — better |
| Further details — not scored | ||
| Size | 3 MB | 8 MB |
| Age rating | 4+ | 4+ |
| Developer | Yasuyoshi Ota | Jinan Matrix Information Technology Co., Ltd. |
Customer experience
NBack for iPad
Data Structure Display
Bugs and requests
NBack for iPad
Not enough reviews yet to summarise bugs or 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
In-app purchases
NBack for iPad
No in-app purchases
Data Structure Display
- Unlock all data structures$2.99
Questions
Is NBack for iPad free?
Is Data Structure Display free?
Which has better reviews, NBack for iPad or Data Structure Display?
Do NBack for iPad or Data Structure Display have ads?
Which is updated more often, NBack for iPad or Data Structure Display?
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