In solving these exercises it is the intention that containers,
algorithms, function objects, iterators, and other standard
components, are to be used as much as possible, if applicable, and
even when it is not explicitly stated. Use containers for storing data
(note, that associative containers store the elements in sorted order;
this one can take advantage of in solving certain problems). Use
algorithms rather than loops, if possible. Use function objects -
predefined or create your own - in combination with algorithms, rather
than using simple functions.