Princess, Flowers and Snake

There are three rooms, and there are Princess, Flowers and Snake in those rooms. The doors of all the rooms have incorrect nameplates. i.e., the nameplate for the princess’ room is not Princess. Similarly, the nameplate for the Flowers’ room is not Flowers. You need to find the room of the Princess without going to the room of Snake. How do you find?
Answer:
Go to the room which has the nameplate Snake. That will not have Snake.
If the room has princess, you are done.
If the room has flowers, then go to the room which has nameplate flowers. Princess would be there in that room. Since, Princess cannot be there in the room which has nameplate Princess.