photo-pair-sequence.rb

<<-LRUG Hola El Rug,

Here's a little teaser for you...

I have two sets of photos; we'll call them urban and nature.  Both sets contain about 6-9 photos, but not necessarily the same number.

I also have about 15-20 pages on a site, spread more or less evenly across three sections.  Each page has a title unique to its section (and, if it helps, we can assume unique across all the pages).

On each page I want to display one photo from each set.

The constraints in descending order are:

* The code should change as little as possible when I add or remove a page or photo.
* We should use each photo at least once.
* A combination of [urban photo, nature photo] should not appear on more than one page.
* And we should try to use all the photos roughly uniformly.

Your time starts...now!
LRUG

U = ["a","b","c","d", "e", "f", "g", "h", "i"]
N = ["u", "v", "w", "x", "y", "z"]

def s(i, u, n)
  u_index = i%(u.length)
  n_offset = i/(u.length)
  n_index = (u_index+n_offset)%(n.length)
  [u[u_index], n[n_index]]
end

results = {}

0.upto(50) do |i|
  value = s(i, U, N)
  puts value.inspect
  results[value] ||= 0
  results[value] += 1
end

# every combo happens once
puts results.values.uniq

Lovely.