.rbenv-version

1.9.3-p327

puzzle_solvers.rb

# encoding: utf-8

# for http://adventure.cueup.com/

def roulette
  def lcg_next(previous, modulus, multiplier, increment)
    ((multiplier*previous) + increment) % modulus
  end

  seed = 6 # use the VAX result as the next seed, not the roulette
  m_mod = 2 ** 32
  a_multiplier = 69069
  c_increment = 1
  vax_result = lcg_next(seed, m_mod, a_multiplier, c_increment)
  puts "VAX: " + vax_result.to_s
  roulette_answer = vax_result % 36
  puts "roulette: " + roulette_answer.to_s
end
roulette

def bugs_rabbit
  def index_of_balance_error(brackets_string)
    index_of_balance_error_recursive(brackets_string.split(//), [], 0)
  end

  def index_of_balance_error_recursive(brackets_remaining, opening_bracket_stack, index)
    opening_brackets = ['{', '[', '(']
    closing_brackets = ['}', ']', ')']
    closing_bracket_for_opener = {'{'=>'}','['=>']','('=>')'}
  
    trace = false
    if trace
      puts
      p [brackets_remaining, opening_bracket_stack, index]
    end
  
    if brackets_remaining.size == 0 # base case
      # I could check that the open bracket stack is not full here,
      # but that’s not necessary for this problem
      return nil
    else
      this_bracket, other_brackets =
       brackets_remaining[0], brackets_remaining[1..-1]
     
      if opening_brackets.include?(this_bracket)
      
        index_of_balance_error_recursive(other_brackets, opening_bracket_stack+ [this_bracket], index+1)
      
      elsif closing_brackets.include?(this_bracket)
      
        top_opening_bracket = opening_bracket_stack[-1]
        if this_bracket != closing_bracket_for_opener[top_opening_bracket]
          return index
        else
          index_of_balance_error_recursive(other_brackets, opening_bracket_stack[0...-1], index+1)
        end
      
      else
      
        raise "input ‘#{this_bracket}’ is not a bracket"
      
      end
    end
  end

  input_brackets = '{]'
  result = index_of_balance_error(input_brackets)
  puts "input: " + input_brackets
  if result
    puts "error at index " + result.to_s
  else
    puts "no closing balance error"
  end
end
# bugs_rabbit

def troll_map
  # solved by hand
  # just note that you can double back
  # my solution was north, east, east, north, east, east, west, north, north, east
end