Sequence of characters problem

I have a sequence of characters. The characters are ordered in chronological order. I am looking for an algorithm to group the sequence and remove errors in the data. I am having an hard time to explain in words/maths what the requirement of fixing the sequence is but something like “the outcome is to group as many characters as possible in a chain of constant letters” and minimum sequence length should be a setting. Below I am trying to visualize by some examples what I mean (3 chars minimum):






And for longer sequences it becomes a little more tricky




This is bit tricky because even thought the 3 O’s aren’t directly next to each other, they are still the most probable uninterrupted sequence of characters.

Does anyone know of any algorithm (Machine learning?) or similar (term of this problem, problem name) that can do this type of error-code correction?

Thank you in advance

Firstly, welcome to the forums.

While we are primarily here to help people with their Free Code Camp progress, we are open to people on other paths, too. Some of what you are asking is pretty trivial in the Free Code Camp context, so you might find that if you’re not getting the instruction and material you need in your current studies, the FCC curriculum will really help you get started. At a modest guess I’d say investing a 4-5 hours working through the curriculum here will really pay off. You can find the curriculum at

With your current questions, we don’t have enough context to know what you already know or don’t know, so it is impossible to guide you without just telling you the answer (which we won’t do).

It is pretty typical on here for people to share a codepen / / jsfiddle example of what they have tried so that anyone helping has more of an idea of what help is actually helpful.

Please provide some example of what you’ve tried and I’m sure you’ll get more help.

Happy coding :slight_smile: