hanoi-ruby.rb

def _log(a,b)
  "move top disk from peg #{a} to peg #{b} \n"
end

def hanoi(n, s={from: 1, free: 2, to: 3})
  return _log(s[:from], s[:to]) if n == 1
  
  hanoi(n-1, {from: s[:from], free: s[:to], to: s[:free]}) + 
  _log(s[:from], s[:to]) + 
  hanoi(n-1, {from: s[:free], free: s[:from], to: s[:to]}) 
end

puts hanoi(4)