gistfile1.rb

def gen_keys(start, offset, count)
  [start] + (1..count).to_a.map {|idx| start+offset*idx}
end

seen = {}
start_pos = (1..16).to_a
test_count = 1_000_000

loop do
  puts "starting positions #{start_pos.inspect}"
  next_start_pos = []
  start_pos.each do |x|
    keys = gen_keys(x, 16, test_count)
    next_start_pos << keys[-1]

    keys.each do |j|
      if seen.has_key?(j)
        puts "FAIL: collission #{j}"
        exit
      end

      seen[j] = true
    end
  end
  seen = {}
  start_pos = next_start_pos
end