Find common values in map

Is there a way to find out if a map contains common values?

1 : 2
2 : 5
3 : 2
4 : 6
5 : 2

above keys 1, 3 and 5 have common values.

I am trying not to use a loop if possible.

I looked at the map key compare and value compare functions but not sure if that’s achieves what I am trying to do.

Edit: Im interested in seeing if there are any member functions of map or any other functions I can use.