Basic Combinatorics for Programmers

Man only likes to count his troubles, but he does not count his joys.
~Fyodor Dostoevsky
What is Combinatorics?
Combinatorics is the math behind counting. All problems that start with the phrase “How many ways..” are most likely combinatorics problem.
Who is this page for?

Programmers who have a simple background in Mathematics, or need a quick reference for how [...]

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Basic Speed Optimizations for the Evil

We should forget about small efficiencies, say about 97% of the time: premature optimization is the root of all evil.
~Donald Knuth
You’ve designed and written your application. You’ve carefully analyzed the algorithm, and it can’t possibly have a lower algorithmic complexity and still do its job. However, your program is still taking 11 seconds to [...]

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