tvl-depot/assessments/semiprimes

Semiprimes Service

Introduction

A composite is a number containing at least two prime factors. For example:

15 = 3 × 5
9 = 3 × 3
12 = 2 × 2 × 3

There are ten composites below thirty containing precisely two, not necessarily distinct, prime factors: 4, 6, 9, 10, 14, 15, 21, 22, 25, 26. Let’s call such numbers Semiprimes.

Task

• Write a module which provides a function to tell whether a given number, N, is a semiprime. N will be less than 100,000
• Please implement an API (RESTful or GraphQL) to factor a given number into two prime numbers if it’s a semiprime, otherwise, return an error message.

Stretch Goals

• Handle the invalid inputs.
• Support batch requests: i.e. users could provide 100 numbers, and the API return the answer for all.
• Considering this module will be used by a long running service, could you optimize it to give answers faster?

Usage

To run the application you'll need to have elixir installed. Assuming elixir is already installed, consult the following steps to start the application:

$ cd server
$ mix deps.get
$ iex -S mix

Now open a web browser and visit http://localhost:8080!