Create VerticesNearbyProblem

You are given an adjacency matrix implementation of an unweighted, directed graph – the
graph has vertices labelled with indices 0 through n-1, and you are given the value n and a
two-dimensional array with n rows and n columns, both indexed from 0 through n-1. You
want to write a method that takes those two values (the integer n and an int** to the
two-dimensional array) and returns a 1 if the distance from any vertex to any other vertex is
always 2 or less, and returns a 0 if there is at least one vertex for which the minimum distance
to some other vertex is 3 or more. You are allowed to create additional one-dimensional arrays
if you need to.