/**
* Tests whether this set is a subset of the specified set.
* It is assumed that the specified set is an instance of
* the MultisetAsArray class.
*
* @param object IMultiset $set The set to compare with this set.
* @return boolean True if the this set is a subset of the specified set;
* false otherwise.
*/
public function isSubset(IMultiset $set)
{
if ($this->getClass() != $set->getClass()) {
throw new TypeError();
}
if ($this->universeSize != $set->universeSize) {
throw new ArgumentError();
}
for ($item = 0; $item < $this->universeSize; ++$item) {
if ($this->array[$item] <= $set->array[$item]) {
return false;
}
}
return true;
}
/**
* Tests whether this multiset is a subset of the specified multiset.
* It is assumed that the specified multiset is an instance of
* the MultisetAsLinkedList class.
*
* @param IMultiset $multiset The multiset to compare with this multiset.
* @return boolean
* True if the this multiset is a subset of the specified multiset;
* false otherwise.
*/
public function isSubset(IMultiset $set)
{
if ($this->getClass() != $set->getClass()) {
throw new TypeError();
}
if ($this->universeSize != $set->universeSize) {
throw new ArgumentError();
}
$p = $this->list->getHead();
$q = $set->list->getHead();
while ($p !== NULL && $q !== NULL) {
$diff = $p->getDatum() . compare($q->getDatum());
if ($diff == 0) {
$p = $p->getNext();
$q = $q->getNext();
} elseif ($diff > 0) {
$q = $q->getNext();
} else {
return false;
}
}
if ($p !== NULL) {
return false;
} else {
return true;
}
}
