#fib(0) is
# 1
#end
#fib(1) is
# 1
#end
#fib(n) is
# fib(n-1) + fib(n-2)
#end

#puts fib(100)

require 'yaml'
$memo = {}
if File.exists?("memofib.yaml") then
  File.open("memofib.yaml", "r") do |f|
    mem = YAML.load(f.read)
    $memo = mem if mem
  end
end

memofib(0) is
  1
end
memofib(1) is
  1
end
memofib(n) is
  if $memo.include?(n) then
    $memo[n]
  else
    f = memofib(n-1) + memofib(n-2)
    $memo[n] = f
  end
end

puts memofib(1000)

File.open("memofib.yaml", "w") do |f|
  f.write YAML.dump($memo)
  f.flush
end