import java.util.ArrayList;
import java.util.List;

public class PowersetCombination {

    // Method to generate the powerset of a given set
    public static <T> List<List<T>> generatePowerset(List<T> set) {
        List<List<T>> powerset = new ArrayList<>();
        // Start with the empty subset
        powerset.add(new ArrayList<>());
        // Iterate over each element in the original set
        for (T element : set) {
            // Temporary list to store new subsets generated in this iteration
            List<List<T>> newSubsets = new ArrayList<>();
            // For each existing subset, create a new subset that includes the current element
            for (List<T> subset : powerset) {
                List<T> newSubset = new ArrayList<>(subset);
                newSubset.add(element);
                newSubsets.add(newSubset);
            }
            // Add the newly created subsets to the powerset
            powerset.addAll(newSubsets);
        }
        return powerset;
    }

    public static void main(String[] args) {
        List<Integer> set = List.of(1, 2, 3);
        List<List<Integer>> powerset = generatePowerset(set);
        System.out.println("Powerset: " + powerset);
    }
}