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<?php |
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namespace DataStructures\Lists; |
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use DataStructures\Lists\Interfaces\ListInterface; |
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abstract class ListAbstract implements ListInterface { |
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protected $size; |
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/** |
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* Insert a node in the specified list position. |
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* |
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* @param integer $index position |
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* @param mixed $data data to be saved |
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*/ |
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public function insert($index, $data) { |
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if($index < 0) { |
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throw new OutOfBoundsException(); |
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} |
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if($index === 0) { |
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$this->insertBeginning($data); |
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} else if($index >= $this->size) { |
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$this->insertEnd($data); |
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} else if($index > 0 && $index < $this->size) { |
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$this->insertAt($index, $data); |
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} |
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$this->size++; |
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} |
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/** |
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* Add a new node in the specified index. |
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* |
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* @param integer $index the position. |
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* @param mixed $data the data to be stored. |
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*/ |
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protected abstract function insertAt($index, $data); |
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/** |
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* Add a new node in the specified index. |
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* |
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* @param mixed $data the data to be stored. |
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*/ |
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protected abstract function insertEnd($data); |
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/** |
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* Inserts at the beginning of the list. |
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* |
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* @param mixed $data |
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*/ |
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protected abstract function insertBeginning($data); |
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/** |
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* Removes all nodes of the list. It removes from the beginning. |
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*/ |
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public function clear() { |
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while($this->head !== null) { |
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$this->shift(); |
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} |
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} |
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/** |
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* Binds to count() method. This is equal to make $this->tree->size(). |
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* |
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* @return integer the tree size. 0 if it is empty. |
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*/ |
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public function count() { |
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return $this->size; |
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} |
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/** |
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* Returns the array size. |
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* |
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* @return int the length |
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*/ |
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public function size() : int { |
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return $this->size; |
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} |
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/** |
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* Checks if the list is empty. |
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* |
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* @return boolean true if is empty, else false. |
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*/ |
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public function empty() : bool { |
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return $this->size === 0; |
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} |
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/** |
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* Adds at the end of the list new node containing |
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* the data to be stored. |
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* |
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* @param mixed $data The data |
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*/ |
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public function push($data) { |
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$this->insert($this->size, $data); |
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} |
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/** |
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* Adds at the beginning a node in the list. |
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* |
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* @param mixed $data |
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* @return mixed the data stored. |
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*/ |
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public function unshift($data) { |
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$this->insert(0, $data); |
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} |
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/** |
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* Deletes the first node of the list and returns it. |
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* |
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* @return mixed the data. |
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*/ |
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public function shift() { |
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return $this->delete(0); |
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} |
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/** |
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* Removes and returns the last node in the list. |
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* |
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* @return mixed data in node. |
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*/ |
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public function pop() { |
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return $this->delete($this->size - 1); |
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} |
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} |