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| -rw-r--r-- | src/datastructures/linkedlists/SinglyLinkedList.java | 160 |
1 files changed, 160 insertions, 0 deletions
diff --git a/src/datastructures/linkedlists/SinglyLinkedList.java b/src/datastructures/linkedlists/SinglyLinkedList.java new file mode 100644 index 0000000..137736c --- /dev/null +++ b/src/datastructures/linkedlists/SinglyLinkedList.java @@ -0,0 +1,160 @@ +/** + * 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; + + +/** + * 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 + * two refence nodes, the first node in the list, + * and the last 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 SinglyLinkedList<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; + + /** + * The last node in the list + */ + public Node tail = 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; + if (this.head == null) + this.tail = node; + 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; + if (this.tail == node) + this.tail = null; + 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; + if (this.tail == predecessor) + this.tail = 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; + if (this.tail == node) + this.tail = predecessor; + return node; + } + + /** + * Insert a value in the end of the list + * + * @param value The value to insert + * @return The node that has be created and inserted + */ + public Node insertEnd(T value) + { + if (this.tail == null) + return insertBeginning(value); + return insertAfter(value, this.tail); + } + +} + |