June 2017
Beginner
330 pages
7h 30m
English
Content preview from Comprehensive Ruby Programming
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Implementing a permutation algorithm
In this section, we are going to build an algorithm that is going to leverage a number of powerful Ruby methods. The math problem that we are going to solve is a problem that asks this: what is the millionth lexicographic permutation of the digits 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9?
This may seem like an intimidating problem, but thankfully, it can be solved quickly with Ruby, thanks to some functional programming methods.
So what is a lexicographic permutation? It's the number of permutations you can make with a given set of numbers. For example, there are six different numbers you can create with the digits 0, 1, and 2.
Now that we know how to build a permutation for three numbers, we have to find the ...
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