From 7161bfab379228d76884df313d55d15b06f9054d Mon Sep 17 00:00:00 2001 From: Mattias Andrée Date: Thu, 23 Jan 2014 07:53:32 +0100 Subject: add sentinel doubly linked list MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Signed-off-by: Mattias Andrée --- .../linkedlists/SentinelDoublyLinkedList.java | 50 ++++++++++++++++++++++ src/datastructures/linkedlists/sentinel-template | 2 +- 2 files changed, 51 insertions(+), 1 deletion(-) create mode 100644 src/datastructures/linkedlists/SentinelDoublyLinkedList.java diff --git a/src/datastructures/linkedlists/SentinelDoublyLinkedList.java b/src/datastructures/linkedlists/SentinelDoublyLinkedList.java new file mode 100644 index 0000000..11ab04a --- /dev/null +++ b/src/datastructures/linkedlists/SentinelDoublyLinkedList.java @@ -0,0 +1,50 @@ +/** + * 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 . + */ +package datastructures.linkedlists; + + +/** + * Sentinel doubly 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 doubly linked list + * stores nodes with references to the both the + * following node previous 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 + * or previous 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 The value stored in the structure + */ +public class SentinelDoublyLinkedList +£>export with_prev=1 +£>$GPP -s £ < src/datastructures/linkedlists/sentinel-template | sed -e '/^[/ ]\*/d' + diff --git a/src/datastructures/linkedlists/sentinel-template b/src/datastructures/linkedlists/sentinel-template index 6d53ce5..43bebab 100644 --- a/src/datastructures/linkedlists/sentinel-template +++ b/src/datastructures/linkedlists/sentinel-template @@ -190,7 +190,7 @@ */ public Node removeEnd() { - return removeEnd(this.edge); + return removeBefore(this.edge); } £>fi -- cgit v1.2.3-70-g09d2