The prisoner boxes riddle solution simulation

boxes.rb

#
# https://www.youtube.com/watch?v=vIdStMTgNl0
#

$SUCCESS = 0
$M = 1_000_000

$N = 10
puts Time.now

def graph_method(i, tries)
  (1..tries).inject([i, false]) do |a,e|
    c = $BOXES[a[0]]
    [ c, a[1] || c == i]   
  end[1]
end


$M.times do |m|
  $BOXES = (0..($N-1)).to_a.shuffle
  #puts $BOXES.inspect

  result = (0..($N-1)).map do |i|
    graph_method(i, 5)
  end.to_a.none?{|x| !x }
  $SUCCESS += 1 if result
end

puts $M
puts $SUCCESS
puts $SUCCESS / $M.to_f

### SAMPLE OUTPUT:
# 2016-10-04 15:03:06 +0200
# 1000000
# 354068
# 0.354068
#