codingame : Conway series ; this script fails to few tests but should be OK and very quick. All the job is done with regular expression that do "group by", and perform string length. This algorithm is called "lookandsay" and is visible somewhere. keywords : codingame, ruby, conway sequence, look'say, look-and-say

codingame-conway.rb

def conway(start, count)
   str=start
   (count-1).times do
		str = str.gsub(/(.)\1*/) {$&.length.to_s + $1}
   end
   return str.split('').join(' ')
end

# read data from STDIN or from FILES passed as args and split as lines
lines=ARGF.read.split("\n")
puts conway(lines[0], lines[1].to_i)

codinggame-conway.rb

# this one is OK for numbers greater > 9
def conway(start, _count)

   seq = [start]
   _seq = []
   (_count-1).times do
      current=seq[0]
      count=0
      seq.each_with_index do |v, i|
         if seq[i]!=current
            _seq << count
            _seq << current
            current=seq[i]
            count=1
         else
            count+=1
         end
      end
      
      _seq << count
      _seq << current
      
      seq = _seq.clone
      _seq = []
   end
   
   return seq.join(" ")
end

# read data from STDIN or from FILES passed as args and split as lines
lines=ARGF.read.split("\n")
puts conway(lines[0].to_i, lines[1].to_i)