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/**
* Copyright © 2014 Mattias Andrée (maandree@member.fsf.org)
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package datastructures.linkedlists;
/**
* Taileess singly linked list class. A linked list
* is a list constructed from nodes, which hold
* stored values, with references to each other,
* this is usally an ineffective data structure,
* especially on high-level object orientated
* languages. A singly linked list only stores nodes
* with references to the following node. It also
* stores one refence nodes, the first node in the
* list. The implemention only implements methods
* that do not require iterating over all nodes for
* find a specific; all other methods' — those that
* are implemented — time complexity is Θ(1).
*
* @param <T> The value stored in the structure
*/
public class TaillessSinglyLinkedList<T>
{
/**
* Node for the list
*/
public class Node
{
/**
* Constructor
*
* @param value The value to store in the list
*/
private Node(T value)
{
this.value = value;
}
/**
* The value stored in the list by this node
*/
public T value;
/**
* The next node in the list
*/
public Node next = null;
}
/**
* The first node in the list
*/
public Node head = null;
/**
* Insert a value in the beginning of the list
*
* @param value The value to insert
* @return The node that has be created and inserted
*/
public Node insertBeginning(T value)
{
Node node = new Node(value);
node.next = this.head;
this.head = node;
return node;
}
/**
* Remove the node at the beginning of the list
*
* @return The node that has been removed
*/
public Node removeBeginning()
{
Node node = head;
if (node != null)
head = head.next;
return node;
}
/**
* Insert a value after a specified, reference, node
*
* @param value The value to insert
* @param predecessor The reference node
* @return The node that has be created and inserted
*/
public Node insertAfter(T value, Node predecessor)
{
Node node = new Node(value);
node.next = predecessor.next;
predecessor.next = node;
return node;
}
/**
* Remove the node after a specified, reference, node
*
* @param predecessor The reference node
* @return The node that has been removed
*/
public Node removeAfter(Node predecessor)
{
Node node = predecessor.next;
if (node == null)
predecessor.next = node.next;
return node;
}
}
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