Array2D CombinationWithDuplicatedElementsByNonRecursion(Array1D array, int K)
{
Array2D result;
if (array.empty() || K <= 0) { return result; }
if (array.size() < K) {
result.push_back(array); /** @warning maybe exclude it */
return result;
}
std::sort(array.begin(), array.end());
result.push_back(Array1D());
int last = array[0], opt_result_num = 1;
for (int i = 0; i < array.size(); i++) {
if (array[i] != last) {
last = array[i];
opt_result_num = result.size();
}
Array2D::size_type result_size = result.size();
for (int j = result_size - 1; j >= result_size - opt_result_num; j--) {
result.push_back(result[j]);
result.back().push_back(array[i]);
}
}
return result;
}
