Booking.com Interview Question

I would say do a 60/40 split between data structures and algorithms respectively. Because even if they give you some hints to the right algorithm you still need to figure out your Data structure and how you would store and retrieve that data. For example: if you say you would use a trie then you should be able to answer why, be able to code it, be able to modify it according to new constraints they introduce on the spot, know about suffix tries etc etc