struct Operation {
int operation_nr;
int time;
};
vector<list<Operation>> tasks(num_tasks);
for(size_t i = 0; i < num_of_lists; ++i)
for(size_t j = 0; j < num_elements_in_list; ++j)
cin >> operation_nr;
cin >> time;
tasks[i].push_back(operation_nr, time);