As is Stephan's nature, he elaborates on technical details in very substantive way. The Standard Template Library, or STL, is a C++ library of container classes, algorithms, and iterators. STL provides many fundamental algorithms and data structures. Furthermore, the STL is a general-purpose library: its components are heavily parameterized, such that almost every component in the STL is a template.
In part 5, Stephan digs into the gory details of the member functions employed by his Nurikabe puzzle solver. You must watch part 4 before watching this part!!
See the other parts of this lecture series:
Books mentioned by Stephen:
The C++ Standard Library: A Tutorial And Reference by Nicolai M. Josuttis
Effective STL by Scott Meyers