bench/shootout/binarytrees.ruby-2.ruby

   1 # The Computer Language Shootout Benchmarks
   2 # http://shootout.alioth.debian.org
   3 #
   4 # contributed by Jesse Millikan
   5
   6 def item_check(tree)
   7  if tree[0] == nil
   8   tree[1]
   9  else
  10   tree[1] + item_check(tree[0]) - item_check(tree[2])
  11  end
  12 end
  13
  14 def bottom_up_tree(item, depth)
  15  if depth > 0
  16   item_item = 2 * item
  17   depth -= 1
  18   [bottom_up_tree(item_item - 1, depth), item, bottom_up_tree(item_item, depth)]
  19  else
  20   [nil, item, nil]
  21  end
  22 end
  23
  24 max_depth = ARGV[0].to_i
  25 min_depth = 4
  26
  27 max_depth = min_depth + 2 if min_depth + 2 > max_depth
  28
  29 stretch_depth = max_depth + 1
  30 stretch_tree = bottom_up_tree(0, stretch_depth)
  31
  32 puts "stretch tree of depth #{stretch_depth}\t check: #{item_check(stretch_tree)}"
  33 stretch_tree = nil
  34
  35 long_lived_tree = bottom_up_tree(0, max_depth)
  36
  37 min_depth.step(max_depth + 1, 2) do |depth|
  38  iterations = 2**(max_depth - depth + min_depth)
  39
  40  check = 0
  41
  42  for i in 1..iterations
  43   temp_tree = bottom_up_tree(i, depth)
  44   check += item_check(temp_tree)
  45
  46   temp_tree = bottom_up_tree(-i, depth)
  47   check += item_check(temp_tree)
  48  end
  49
  50  puts "#{iterations * 2}\t trees of depth #{depth}\t check: #{check}"
  51 end
  52
  53 puts "long lived tree of depth #{max_depth}\t check: #{item_check(long_lived_tree)}"
  54
  55