ID Overlap checking algorithm

Question

Example, the server has these ids:
aaaa, aaaa - 1 , aaaa - 2 , bbbb

If the client sign in, the server check client's algorithm
If the client's id is aaaa, server make client's id aaaa - 3
If the client's id is bbbb, server make client's id bbbb -1

How can i do that?

Answer 1

• Make a hash table that stores the number of times an id has been seen.
• Check the hash table to see if an id has been seen:
  • If so, increment and return the number
  • If not, make a new entry and set to 0.