Ruby: Solution to Project Euler Problem # 53

http://projecteuler.net/problem=53

Combinatoric selections

There are exactly ten ways of selecting three from five, 12345:
123, 124, 125, 134, 135, 145, 234, 235, 245, and 345
In combinatorics, we use the notation, 5C3 = 10.

where r n, n! = n(n1)…321, and 0! = 1.

How many, not necessarily distinct, values of  nCr, for 1 ≤ n ≤ 100, are greater than one-million?

2 thoughts on “Ruby: Solution to Project Euler Problem # 53

  1. Mateus

    Does this count as solution a for this problem?


    value = 12345
    result = value.to_s.scan(/.{1,1}/).combination(3).to_a.map { |e| e.join.to_i }
    p result

    Reply

Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>