PB'16 competition: WBO track: memory versus time to solve an instance

These graphs are based on a sampling of the memory usage of the solver which is performed every ten seconds. Therefore, this data is not necessarily very accurate since a solver may allocate and deallocate a lot of memory in ten seconds. Besides, when a solvers runs for less than ten seconds, no information on its memory usage could be recorded. Also, solvers written in the Java programming language usually allocate all their memory at once at the beginning of the program and therefore the reported memory is not very meaningful.