Convert in less than 30 lines

challenge.rb

LIST = [['A','B','C'], ['A','C','E'], ['E','F','D'],['D','A','J'],['E','D','J']]
out = Hash.new(0)
LIST.each do |row|
  arr = row.sort + row.sort
  3.times { out[[arr.shift,arr.shift].sort] += 1 }
end
for key in out.keys.sort do
  puts "#{key.join(", ")}, #{out[key]}"
end

gistfile1.txt

Question: Convert following into the latter data structure in less than 30 lines:

List:
  A, B, C
  A, C, E
  E, F, D
  D, A, J
  E, D, J

List
  A, B, 1 (frequency)
  A, C, 2
  A, D, 1
  A, E, 1
  A, J, 1
  B, C, 1
  C, E, 1
  D, E, 2
  D, F, 1
  D, J, 2
  E, F, 1
  E, J, 1