int N;
std::ifstream in("file.in");
in >> N;

int **array = new int[N][N]; // ?

    int **array = new (int *)[N];   // array is a dynamically allocated array of pointers to int
       for (int i = 0; i < N; ++i)
       array[i] = new int [N];    // and each pointer in array is now a dynamically allocated array of int

typedef int element;
typedef std::vector<element> row;
typedef std::vector<row> two_d;

int N = 10;

two_d collection(N, row(N, 0));        // NxN elements initialezed to 0.

collection.at(0).at(0);

collection[0][0];

two_d::const_iterator td_iter = collection.begin();
row::const_iterator iter = td_iter->begin();