Class TreeMap<K,V> | Lower and Upper Count Support

[mayank bansal]

Hi Everyone,

I would like to propose and work on a feature request of supporting the
lower and higher count in java class TreeMap.
"lower count" is the number of elements that are strictly less than the
given value.
"upper count" is the number of elements that are strictly greater than the
given value.

*Method definitions-*
int getLowerCount(K key);
int getHigherCount(K key);

*Follow-up feature -*
Class TreeSet<E> constructor initializes the TreeMap<K,V> in the TreeSet
constructor.
It puts the dummy value as *new Object()* whenever we add the entry in
TreeSet.
I would like to work on the feature to provide the *Duplicate count* in
case of the same Key and the same Value.

I will be happy to work on both and raise a PR. I need some guidance if the
proposed feature looks good and I can start working on it and also would
like to know about the process whether I can directly raise the PR.

Thanks
-- 
Regards,
Mayank Bansal