adding to vector of vector<int>, check if element already present

[Paul McKenzie]

What is "path_count"? Where does it come from? Also, why do you need to keep a count? Why are you not iterating over a range instead of trying to "hand_count" using path_count?

In other words:

for_each(new_set_of_paths.begin(), 
               new_set_of_paths.end(), whatever);

The "whatever" can be ironed out later, but is this what your major loop (which you didn't show us) consist of?

Regards,

Paul McKenzie