# Java Data Structures & Algo vs PerciFi

The clearest difference is in-app purchases: Java Data Structures & Algo at none against PerciFi's 2. PerciFi's advantage is update cadence (weekly vs every 3 months) and iOS requirement (13.0 vs 16.0). On price, ads and device support there is nothing between them.

Both are free to download. PerciFi sells 2 in-app purchases, starting at $14.99 per month. Java Data Structures & Algo asks for nothing beyond the download.

Java Data Structures & Algo ships an update every 3 months, PerciFi weekly. The most recent releases landed on September 27, 2026 and September 7, 2026 respectively.

## The numbers

| Metric | Java Data Structures & Algo | PerciFi |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[5.0 (6 ratings)](https://appshunter.io/ios/app/percifi/id6758317727/reviews)** |
| Number of ratings | — | **6** |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 3 months | **Weekly** |
| Monetization | — | Free with in-app purchases |
| Size | 18 MB | 52 MB |
| Requires iOS | 16.0 | **13.0** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [ALG Software Lab](https://appshunter.io/developer/1650561236) | [Zahan Meyer](https://appshunter.io/developer/1848614992) |

## What reviewers say

### Java Data Structures & Algo

[App page](https://appshunter.io/ios/app/java-data-structures-and-algo/id6756706722)

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


### PerciFi

[App page](https://appshunter.io/ios/app/percifi/id6758317727)

This app makes learning about Bitcoin and blockchain technology simple and interactive. It covers fundamental concepts, wallet security, DeFi, and NFTs through easy-to-digest lessons.

**Highlights:** Bite-sized interactive lessons, Bitcoin and blockchain fundamentals, Wallet security and self-custody, DeFi protocols and yield strategies, NFT basics and marketplace navigation

**Features:** macOS Compatibility

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| PerciFi Pro - Monthly | $14.99 | per month |
| PerciFi Pro - Annual | $99.99 | per year |


## Frequently asked questions

### Is Java Data Structures & Algo free?

Java Data Structures & Algo is free to download, with no in-app purchases.

### Is PerciFi free?

PerciFi is free to download, with in-app purchases available.

### Do Java Data Structures & Algo or PerciFi have ads?

Neither Java Data Structures & Algo nor PerciFi shows ads.

### Which is updated more often, Java Data Structures & Algo or PerciFi?

Java Data Structures & Algo ships an update every 3 months, and PerciFi weekly. Most recently, Java Data Structures & Algo was updated on September 27, 2026 and PerciFi on September 7, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*