/room_allocation

it will take a input of arrange of bookings hash data and number of rooms

bookings = [{
  "checkin": "2017-10-1",
  "checkout": "2017-10-3",
  "id" : 1
},
{
  "checkin": "2017-10-1",
  "checkout": "2017-10-4",
  "id" : 2
},
{
  "checkin": "2017-10-3",
  "checkout": "2017-10-6",
  "id" : 3
},
{
  "checkin": "2017-10-3",
  "checkout": "2017-10-8",
  "id" : 4
},
{
  "checkin": "2017-10-4",
  "checkout": "2017-10-8",
  "id" : 5
},
{
  "checkin": "2017-10-8",
  "checkout": "2017-10-12",
  "id" : 6
},
{
  "checkin": "2017-10-9",
  "checkout": "2017-10-20",
  "id" : 7
},
{
  "checkin": "2017-10-15",
  "checkout": "2017-10-20",
  "id" : 8
},
{
  "checkin": "2017-10-21",
  "checkout": "2017-10-30",
  "id" : 9
}]

num_of_rooms = 3

result = assign_rooms(bookings, num_of_rooms)

#returns following
[
    [1,3,6,8,9],
    [2,5,7],
    [4]
]