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package bjc.utils.funcutils;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
public class SetUtils {
public static <T> Set<Set<T>> powerSet(Set<T> originalSet) {
Set<Set<T>> sets = new HashSet<Set<T>>();
if (originalSet.isEmpty()) {
sets.add(new HashSet<T>());
return sets;
}
List<T> list = new ArrayList<T>(originalSet);
T head = list.get(0);
Set<T> rest = new HashSet<T>(list.subList(1, list.size()));
for (Set<T> set : powerSet(rest)) {
Set<T> newSet = new HashSet<T>();
newSet.add(head);
newSet.addAll(set);
sets.add(newSet);
sets.add(set);
}
return sets;
}
public static <T> Set<T> toSet(T... elms) {
Set<T> set = new HashSet<>();
for(T elm : elms) {
set.add(elm);
}
return set;
}
}
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