Category Archives: computer science

Combinations Part 5 – (wrapping it up)

The original problem as posed by Eric Lippert was to write a function to produce all the combinations of k elements from a collection of n elements. So far I’ve ported the code to product all the combinations of k … Continue reading

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Combinations – Part 4 (combinations of booleans)

In this article we’ll implement the combinations function from Eric Lippert’s post. Here he implements a function that returns all the combinations of n booleans with k of them set to true. See part 3 of his series. Let’s implement … Continue reading

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Combinations – Part 3 (SequenceOf extensions)

I want to continue on with my implementation of Combinations. But first, when working on this problem I determined I really needed some helper methods on SequenceOf. Initially these were very complicated but as my comfort level increased I figured … Continue reading

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Combinations – Part 2

Last time I started working on the combinations problem that Eric Lippert wrote about: We’ll be working a lot with SequenceType, SequenceOf, GeneratorType and GeneratorOf. I’m more familiar with the enumerating type of C# (IEnumerable and IEnumerator). Together SequenceType and … Continue reading

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Combinations – Part 1

I’ve had a difficult time trying to understand the collections in the Swift programming language from Apple. In particular, I’ve been trying to identify the analog of the IEnumerable type from C#. I don’t think there is one. As an … Continue reading

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Loop Invariant Proofs

Sometime last year I ran across a blog talking about loop invariant proofs. At the time it seemed like a new concept to me. My undergraduate degree was not in computer science, and my graduate degree in computer science was … Continue reading

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