My legacy code uses a red-black tree to store pointers to homogeneous (typically POD) objects. Let's call one MyPod. My compare function compares pointers to two such objects based on whatever criteria is required. What I'm trying to find isn't a SECOND thing, but just the pointer already in the red-black tree.
To use std::map<> I think I'd have to map std::Map<MyPod*, MyPod*>? Seems wasteful to have the same pointer twice. Is there another collection I should consider? Can I make the second item void, or replace the pair<> with a single pointer, or make the pair a union, or something?
You can just use std::set<MyPod*> instead of a std::Map<MyPod*, MyPod*>.