sunchen115

require 'date'



def days_between(date1, date2)
  d1 = Date.parse(date1)
  d2 = Date.parse(date2)
  (d2 - d1).to_i
end

sunchen115

ss=%w{JP OYJC欧阳继超 FJ冯佳 SC孙晨}.sort
pairs=[]
ss.each do |e1|
  ss.each do |e2|
    if e1 != e2
      pairs<<[e1,e2].sort unless pairs.include?([e1,e2].sort)
    end
  end
end