Ransom Note problem in F#

A problem that has shown up multiple times in my preparation for technical interviews is the so called Ransom Note problem.

To solve this in F# is pretty simple.

In the interest of efficiency I decided to use a mutable Dictionary instead of the F# Map to store the no. of times a letter appears in the ransom note.

There’s also an optimization here to stop iterating through the magazine once all the letters for the ransom note is accounted for. One way to do it is to use Seq.takeWhile and mutate the Dictionary as we iterate through letters in the magazine, and stop when letters.Count = 0.

 

Try it Yourself

 

Links

Liked this article? Support me on Patreon and get direct help from me via a private Slack channel or 1-2-1 mentoring.
Subscribe to my newsletter


Hi, I’m Yan. I’m an AWS Serverless Hero and the author of Production-Ready Serverless.

I specialise in rapidly transitioning teams to serverless and building production-ready services on AWS.

Are you struggling with serverless or need guidance on best practices? Do you want someone to review your architecture and help you avoid costly mistakes down the line? Whatever the case, I’m here to help.

Hire me.


Check out my new course, Complete Guide to AWS Step Functions. In this course, we’ll cover everything you need to know to use AWS Step Functions service effectively. Including basic concepts, HTTP and event triggers, activities, callbacks, nested workflows, design patterns and best practices.

Get Your Copy