Question

Given a list of [FileName, FileSize, [Collection]] - Collection is optional, i.e., a collection can have 1 or more files. Same file can be a part of more than 1 collection. How would you design a system? To calculate total size of files processed. To calculate Top K collections based on size. Example: file1.txt(size: 100) file2.txt(size: 200) in collection "collection1" file3.txt(size: 200) in collection "collection1" file4.txt(size: 300) in collection "collection2" file5.txt(size: 100). Output: Top 2 collections: collection1: 400. collection2: 300. Follow up questions: 1] Concurrent calls handling – Synchronization. 2] Trade-off between speed and storage of file information. 3] IF you used list not Set, then why set etc.

Answer 1

To design a system for calculating file sizes and Top K collections, an efficient data structure updating sizes, handling concurrent calls, and managing storage would be implemented. A set would likely be used for collection entries to avoid duplicates.

Step-by-step explanation:

Designing a File and Collection Management System

To design a system that calculates the total size of files processed and identifies the Top K collections based on size, we need to maintain a data structure that efficiently updates and retrieves the size information. This would likely involve a file size table and a separate collection table. Each entry in the file size table would have a file name and its size. The collection table would have a collection name, along with a list or set of files that belong to the collection and the cumulative size of those files.

When new files are added or existing files are assigned to more collections, we would update both tables accordingly. To handle concurrent calls, synchronization mechanisms such as locks or concurrent data structures might be needed to prevent race conditions and ensure data consistency. Regarding the trade-off between speed and storage, using in-memory caches can provide quick access to data at the cost of increased memory usage.

As for the choice between using a list or set for storing file references in collections, a set would prevent duplicate entries, which is important if the same file can be a part of multiple collections. Lists could potentially allow duplicates, which would lead to incorrect size calculations unless additional checks are put in place.

The example provided shows that 'collection1' has a size of 400, due to containing 'file1.txt', 'file2.txt', and 'file3.txt', each file's size contributes to this total. Meanwhile, 'collection2' only consists of 'file4.txt' with a size of 300, making it the second-largest collection in this scenario. To determine the Top 2 collections, we would sort the collections by their cumulative size and pick the top two.