Cartesian Product in c++

Question

I have been searching for weeks on how to come up with piece of code which I could applied the cartesian product. Let\'s say I have two arrays :

int M[2]= {         


        

Answer 1

Here is an implementation where the sequences of values is a parameter (rather than pre-known as in all the other implementations):

void CartesianRecurse(vector> &accum, vector stack,
    vector> sequences, int index)
{
    vector sequence = sequences[index];
    for (int i : sequence)
    {       
        stack.push_back(i);
        if (index == 0)
            accum.push_back(stack);
        else
            CartesianRecurse(accum, stack, sequences, index - 1);
        stack.pop_back();
    }
}
vector> CartesianProduct(vector> sequences)
{
    vector> accum;
    vector stack;
    if (sequences.size() > 0)
        CartesianRecurse(accum, stack, sequences, sequences.size() - 1);
    return accum;
}

main() {
    vector> sequences = { {1,2,7},{3,4},{5,6} };
    vector> res = CartesianProduct(sequences);
    // now do something with the result in 'res'.
}