title: Data structure to be used for implementing online booking system
body: <p>It was asked by a interviewer.</p>
  
  <p>The target is to Design a train tickets Reservation system. If the train go through 5 stations(e.g. A,B,C,D,E). We could sell tickets from A-E or A-B, if a ticket from A-B is sold, we could go on sell tickets between B-E. </p>
  
  <p>The question is which data structure is suitable to present the seats? It should show which section is available for sale.</p>
  
  <p>Thanks for help! </p>