Lemon is a C++ template library providing efficient implementations of common
data structures and algorithms with focus on combinatorial optimization tasks
connected mainly with graphs and networks.

LEMON is a member of the COIN-OR initiative, a collection of OR related open
source projects. You are free to use it in your commercial or non-commercial
applications under very permissive license terms. 

WWW: https://lemon.cs.elte.hu/trac/lemon/