code_war: The observed PIN

code_war: The observed PIN.rb

def get_pins(observed)
 adjacents = []
 chars = observed.chars
  chars.each do |char|
    adjacents << adjacent(char)
  end 
  adjacents.reduce { |acc,el| acc.product el }.map { |el| el.join("")}.sort
end

def adjacent(str)
  adjacent = []
COMBINATION.each_with_index do |el, idx| 

  if el.include?(str) 
     index = el.index(str)
     adjacent << el[index+1] if el[index+1] #left
     adjacent << el[index-1] if index-1 >= 0 #right
     adjacent << COMBINATION[idx-1][index] if idx -1 >= 0
     adjacent << COMBINATION[idx+1][index] if COMBINATION[idx+1][index] #down
     adjacent << str
  end 
 end 
 adjacent

end 

arr = []
arr << ("1".."3").to_a 
arr << ("4".."6").to_a 
arr << ("7".."9").to_a 
arr << [nil, "0", nil] 
COMBINATION = arr