title: C++ Maps for Many-to-Many
body: <p>i need a data structure to store this info so that: (I have MANY -to- MANY )</p>
  
  <p>1 .given an employee i can find out the projects
   2. given the projects i can find the employee</p>
  
  <p>If I use multi map then I will need to maintain 2 maps,
  Is there any other data structure that I can use here? </p>