/**
* Finds an object in this M-way tree that matches
* the specified object.
* Uses linear search.
*
* @param object IComparable $obj The object to match.
* @return mixed An object that matches the specified one;
* NULL if the tree is empty.
*/
public function find(IComparable $obj)
{
if ($this->isEmpty()) {
return NULL;
}
for ($i = $this->count; $i > 0; --$i) {
$diff = $obj->compare($this->key[$i]);
if ($diff == 0) {
return $this->key[$i];
}
if ($diff > 0) {
break;
}
}
return $this->subtree[$i]->find($obj);
}
/**
* Withdraws the specified object from this binary search tree.
*
* @param object IObject $obj The object to be withdrawn from this tree.
*/
public function withdraw(IComparable $obj)
{
if ($this->isEmpty()) {
throw new ArgumentError();
}
$diff = $obj->compare($this->getKey());
if ($diff == 0) {
if (!$this->getLeft()->isEmpty()) {
$max = $this->getLeft()->findMax();
$this->key = $max;
$this->getLeft()->withdraw($max);
} elseif (!$this->getRight()->isEmpty()) {
$min = $this->getRight()->findMin();
$this->key = $min;
$this->getRight()->withdraw($min);
} else {
$this->detachKey();
}
} else {
if ($diff < 0) {
$this->getLeft()->withdraw($obj);
} else {
$this->getRight()->withdraw($obj);
}
}
$this->balance();
}
