Coding Assignment - Prime Numbers
By listing the first six prime numbers: 2, 3, 5, 7, 11 and 13, we can see that the 6th prime is 13. What is the 10 001st prime number?
The number is 104743. The source code is at app/nthprime.js
and the test is at test/nthprime.js. This project took about
30 minutes and uses simple trial division. If time permitted a superior
implementation, that could be based on the sieve of Eratosthenes
or the Meissel-Lehmer algorithm.
Steps to checkout and run the tests locally:
- Ensure you have git and npm installed properly
- Check out this repo with:
git clone https://github.com/manosbatsis/slashdata-coding-assignment.git - Navigate to the project folder:
cd slashdata-coding-assignment - Install with NPM (you may need sudo):
npm install - Run the test:
npm test
Here is the result:
- When would you choose a NoSQL database instead of a relational database and why?
According to project requirements. RDBMS systems address needs like ACID or nested transactions. Various NoSQL solutions available differ greatly in their features, limitations target problem spaces. Some like MongoDB provide flexible and even schema-less, document-based storage but have limited (e.g. per document) transactions support. ElasticSearch provides scalable fulltext search capabilities. Cassandra provides a distributed, “eventually consistent” and "always available" database. Others may be suitable for graph or key-value pair data. The list goes on and on.
So, in short, I would choose a NoSQL database in cases it could be the right tool for the task at hand.
- If you have problems with the performance of SQL queries on data that changes very infrequently, what options are there for improving the performance?
It really depends on the RDBMS used, the size of infrequently changed data, and architecture of the application issuing the queries, A common example would be some level of caching, e.g. second level cache in Hibernate's implementation JPA.
- What are the most important things to consider when designing a web application that has to work well on mobile devices?
Off the top of one's head, the list would include:
- Overall compatibility
- Responsive layout
- Limited hardware resources
- Size of resources in HTTP (or other) traffic
- Off-line use (e.g. using local browser storage temporarily)
- What would you consider an effective development process and collaboration tools for a small remote team of 3 or 4 developers?
It depends on the circumstances involved. Development methodologies are more critical to larger teams,
so in this case a decision could be based on project/client requirements and the team members themselves.
Overall I tend to align with the goals of the agile manifesto without necessarily applying an agile, SCRUM etc. methodology per se. Having distinct roles of a product owner and team lead is important, as well as efficiently utilizing limited development resources properly through TDD, CI etc.