CK>if (vec.capacity() / vec.size() > 2) {
CK>  vector<int> tmp;
CK>  tmp.reserve(vec.size());
CK>  copy(begin(vec), end(vec), back_inserter(tmp));
CK>  swap(tmp, vec);
CK>}

CK>bigAssCollection[key] = move(vec);
CK>