Comparison

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.

Head to head
About

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.

Highlights
  • Working memory training
  • N-Back task implementation
  • Multiple difficulty levels (1'Back to 10'Back)
  • Cognitive ability enhancement
  • iPad optimized
Features
Read full description

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

About

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.

Highlights
  • 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
Features
Read full description

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

Data Structure Display4 screens

Verdict

The call

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

CostPrice · In-app purchases · Ads · Monetization

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.

ReceptionRating · Positive reviews · Number of ratings

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.

UpkeepUpdate frequency

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.

Scorecard9 real differences · 1 level
NBack for iPad versus Data Structure Display: the parameters behind the verdict, then further details
ParameterNBack for iPadData Structure Display
Price$2.99Free — better
Rating5.0 (1 ratings) — better4.5 (676 ratings)
Positive reviews50.0% of reviews61.9% of reviews — better
Number of ratings1676 — better
Update frequencyEvery 12 monthsEvery 5 months — better
AdsNoNo
In-app purchasesNo — betterYes
MonetizationPaidFree with in-app purchases — better
DevicesiPadiPhone, iPad, iPod, Mac — better
Requires iOS18.213.0 — better
Further details — not scored
Size3 MB8 MB
Age rating4+4+
DeveloperYasuyoshi OtaJinan Matrix Information Technology Co., Ltd.

Customer experience

NBack for iPad

All ratings1 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews2 reviews
Positive50.0%
Neutral0.0%
Negative50.0%

Data Structure Display

All ratings676 ratings
Positive87.1%
Neutral2.4%
Negative10.5%
Written reviews42 reviews
Positive61.9%
Neutral2.4%
Negative35.7%

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

None

NBack for iPad

No in-app purchases

1 purchases

Data Structure Display

One-time1
  • Unlock all data structures$2.99

Questions

Is NBack for iPad free?
NBack for iPad costs $2.99, with no in-app purchases.
Is Data Structure Display free?
Data Structure Display is free to download, with in-app purchases available.
Which has better reviews, NBack for iPad or Data Structure Display?
NBack for iPad is rated higher. NBack for iPad averages 5.0 out of 5 from 1 ratings, while Data Structure Display averages 4.5 from 676 ratings.
Do NBack for iPad or Data Structure Display have ads?
Neither NBack for iPad nor Data Structure Display shows ads.
Which is updated more often, NBack for iPad or Data Structure Display?
NBack for iPad ships an update every 12 months, and Data Structure Display every 5 months. Most recently, NBack for iPad was updated on September 16, 2026 and Data Structure Display on September 24, 2026.

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