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-rw-r--r--src/datastructures/linkedlists/DoublyLinkedList.java40
-rw-r--r--src/datastructures/linkedlists/SinglyLinkedList.java2
-rw-r--r--src/datastructures/linkedlists/TaillessSinglyLinkedList.java2
-rw-r--r--src/datastructures/linkedlists/template103
4 files changed, 143 insertions, 4 deletions
diff --git a/src/datastructures/linkedlists/DoublyLinkedList.java b/src/datastructures/linkedlists/DoublyLinkedList.java
new file mode 100644
index 0000000..334eee5
--- /dev/null
+++ b/src/datastructures/linkedlists/DoublyLinkedList.java
@@ -0,0 +1,40 @@
+/**
+ * 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;
+
+
+/**
+ * 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
+ * doublely linked list stores nodes with references
+ * to both the following node and the previous 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 DoublyLinkedList<T>
+£>export with_tail=1 with_prev=1
+£>gpp -s £ < src/datastructures/linkedlists/template | sed -e '/^[/ ]\*/d'
+
diff --git a/src/datastructures/linkedlists/SinglyLinkedList.java b/src/datastructures/linkedlists/SinglyLinkedList.java
index 50814c6..b0bfc51 100644
--- a/src/datastructures/linkedlists/SinglyLinkedList.java
+++ b/src/datastructures/linkedlists/SinglyLinkedList.java
@@ -35,6 +35,6 @@ package datastructures.linkedlists;
* @param <T> The value stored in the structure
*/
public class SinglyLinkedList<T>
-£>export with_tail=1
+£>export with_tail=1 with_prev=0
£>gpp -s £ < src/datastructures/linkedlists/template | sed -e '/^[/ ]\*/d'
diff --git a/src/datastructures/linkedlists/TaillessSinglyLinkedList.java b/src/datastructures/linkedlists/TaillessSinglyLinkedList.java
index a73ab72..6de16b8 100644
--- a/src/datastructures/linkedlists/TaillessSinglyLinkedList.java
+++ b/src/datastructures/linkedlists/TaillessSinglyLinkedList.java
@@ -34,6 +34,6 @@ package datastructures.linkedlists;
* @param <T> The value stored in the structure
*/
public class TaillessSinglyLinkedList<T>
-£>export with_tail=0
+£>export with_tail=0 with_prev=0
£>gpp -s £ < src/datastructures/linkedlists/template | sed -e '/^[/ ]\*/d'
diff --git a/src/datastructures/linkedlists/template b/src/datastructures/linkedlists/template
index 4ea20ad..b0311b5 100644
--- a/src/datastructures/linkedlists/template
+++ b/src/datastructures/linkedlists/template
@@ -43,6 +43,13 @@
*/
public Node next = null;
+£>if (( with_prev )); then
+ /**
+ * The previous node in the list
+ */
+ public Node previous = null;
+£>fi
+
}
@@ -71,6 +78,10 @@
{
Node node = new Node(value);
node.next = this.head;
+£>if (( with_prev )); then
+ if (node.next != null)
+ node.next.previous = node;
+£>fi
£>if (( with_tail )); then
if (this.head == null)
this.tail = node;
@@ -86,9 +97,13 @@
*/
public Node removeBeginning()
{
- Node node = head;
+ Node node = this.head;
if (node != null)
- head = head.next;
+ this.head = this.head.next;
+£>if (( with_prev )); then
+ if (this.head != null)
+ this.head.previous = null;
+£>fi
£>if (( with_tail )); then
if (this.tail == node)
this.tail = null;
@@ -108,6 +123,11 @@
Node node = new Node(value);
node.next = predecessor.next;
predecessor.next = node;
+£>if (( with_prev )); then
+ node.previous = predecessor;
+ if (node.next != null)
+ node.next.previous = node;
+£>fi
£>if (( with_tail )); then
if (this.tail == predecessor)
this.tail = node;
@@ -126,12 +146,76 @@
Node node = predecessor.next;
if (node == null)
predecessor.next = node.next;
+£>if (( with_prev )); then
+ else if (node.next != null)
+ node.next.previous = predecessor;
+£>fi
£>if (( with_tail )); then
if (this.tail == node)
this.tail = 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 be 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;
+ if (node.previous != null)
+ node.previous.next = node;
+ if (this.head == successor)
+ this.head = 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;
+ if (node == null)
+ successor.previous = node.previous;
+ else if (node.previous != null)
+ node.previous.next = successor;
+ if (this.head == node)
+ this.head = successor;
+ return node;
+ }
+
+ /**
+ * Remove the node from the list
+ *
+ * @param node The node to remove
+ */
+ public void remove(Node node)
+ {
+ if (node.previous == null)
+ this.head = node.next;
+ else
+ node.previous.next = node.next;
+
+ if (node.next != null)
+ node.next.previous = node.previous;
+£>if (( with_tail )); then
+ else
+ this.tail = node.previous;
+£>fi
+ }
+£>fi
£>if (( with_tail )); then
/**
@@ -146,6 +230,21 @@
return insertBeginning(value);
return insertAfter(value, this.tail);
}
+
+£>if (( with_prev )); then
+ /**
+ * Remove the node at the end of the list
+ *
+ * @return The node that has been removed
+ */
+ public Node removeEnd()
+ {
+ Node node = this.tail;
+ if (node != null)
+ (this.tail = node.previous).next = null;
+ return node;
+ }
+£>fi
£>fi
}