#include <iostream>
#include <vector>
 
bool increase(const std::vector<std::vector<int>>& v, std::vector<std::size_t>& it)
{
    for (std::size_t i = 0, size = it.size(); i != size; ++i) {
        const std::size_t index = size - 1 - i;
        ++it[index];
        if (it[index] >= v[index].size()) {
            it[index] = 0;
        } else {
            return true;
        }
    }
    return false;
}
 
void do_job(const std::vector<std::vector<int>>& v,
            const std::vector<std::size_t>& it)
{
    for (std::size_t i = 0; i != it.size(); ++i) {
        std::cout << v[i][it[i]] << " ";
    }
    std::cout << std::endl;
}
 
void iterate(const std::vector<std::vector<int>>& v)
{
    std::vector<std::size_t> it(v.size(), 0u);
 
    do {
        do_job(v, it);
    } while (increase(v, it));
}
 
int main(int argc, char *argv[])
{
    std::vector<std::vector<int>> v = {
    	{1,2,3},
    	{4,5},
    	{6,7,8,9},
    	{10,11}
   	};
    iterate(v);
}