diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/datastructures/linkedlists/SentinelSinglyLinkedList.java | 49 | ||||
| -rw-r--r-- | src/datastructures/linkedlists/sentinel-template | 198 |
2 files changed, 247 insertions, 0 deletions
diff --git a/src/datastructures/linkedlists/SentinelSinglyLinkedList.java b/src/datastructures/linkedlists/SentinelSinglyLinkedList.java new file mode 100644 index 0000000..dd1c23f --- /dev/null +++ b/src/datastructures/linkedlists/SentinelSinglyLinkedList.java @@ -0,0 +1,49 @@ +/** + * 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; + + +/** + * Sentinel 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. A sentinel linked list increses + * performance and reduces complexity by tracking + * the edges implicitly rather than explicitly; + * instead of having reference to the first and + * last node, a sentinel linked list have an extra + * node, {@link #edge}, is placed at both the end + * and the beginning of the linked list — the + * list acts as linear but is constructed as + * circular — and rather than checking that the + * next node is not {@code null} you check that it + * is not {@link #edge}. This 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 SentinelSinglyLinkedList<T> +£>export with_prev=0 +£>$GPP -s £ < src/datastructures/linkedlists/sentinel-template | sed -e '/^[/ ]\*/d' + diff --git a/src/datastructures/linkedlists/sentinel-template b/src/datastructures/linkedlists/sentinel-template new file mode 100644 index 0000000..6d53ce5 --- /dev/null +++ b/src/datastructures/linkedlists/sentinel-template @@ -0,0 +1,198 @@ +/* -*- java -*- */ +/** + * 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/>. + */ +{ + /** + * Node for the list + */ + public class Node + { + /** + * Constructor + * + * @param value The value to store in the list + */ + public 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; + +£>if (( with_prev )); then + /** + * The previous node in the list + */ + public Node previous = null; +£>fi + + } + + + + /** + * The sentinel node in the list + */ + public Node edge; + + + + /** + * Initialiser + */ + { + this.edge.next = this.edge; +£>if (( with_prev )); then + this.edge.previous = this.edge; +£>fi + } + + + + /** + * Insert a value in the beginning of the list + * + * @param value The value to insert + * @return The node that has been created and inserted + */ + public Node insertBeginning(T value) + { + return insertAfter(value, this.edge); + } + + /** + * Remove the node at the beginning of the list + * + * @return The node that has been removed + */ + public Node removeBeginning() + { + return removeAfter(this.edge); + } + + /** + * Insert a value after a specified, reference, node + * + * @param value The value to insert + * @param predecessor The reference node + * @return The node that has been created and inserted + */ + public Node insertAfter(T value, Node predecessor) + { + Node node = new Node(value); + node.next = predecessor.next; + predecessor.next = node; +£>if (( with_prev )); then + node.previous = predecessor; + node.next.previous = node; +£>fi + 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; + predecessor.next = node.next; +£>if (( with_prev )); then + predecessor.next.previous = predecessor; +£>fi + return node; + } + +£>if (( with_prev )); then + /** + * Insert a value before a specified, reference, node + * + * @param value The value to insert + * @param successor The reference node + * @return The node that has been created and inserted + */ + public Node insertBefore(T value, Node successor) + { + Node node = new Node(value); + node.previous = successor.previous; + successor.previous = node; + node.next = successor; + node.previous.next = node; + return node; + } + + /** + * Remove the node before a specified, reference, node + * + * @param successor The reference node + * @return The node that has been removed + */ + public Node removeBefore(Node successor) + { + Node node = successor.previous; + successor.previous = node.previous; + successor.previous.next = successor; + return node; + } + + /** + * Remove the node from the list + * + * @param node The node to remove + */ + public void remove(Node node) + { + node.previous.next = node.next; + node.next.previous = node.previous; + } + + /** + * Insert a value in the end of the list + * + * @param value The value to insert + * @return The node that has been created and inserted + */ + public Node insertEnd(T value) + { + return insertBefore(value, this.edge); + } + + /** + * Remove the node at the end of the list + * + * @return The node that has been removed + */ + public Node removeEnd() + { + return removeEnd(this.edge); + } +£>fi + +} + |