In computer science, a doubly linked list is a linked data structure that consists of a set of sequentially linked records called nodes. Each node contains two fields, called links, that are references to the previous and to the next node in the sequence of nodes. The beginning and ending nodes' previous and next links, respectively, point to some kind of terminator, typically a sentinel node or null, to facilitate traversal of the list. If there is only one sentinel node, then the list is circularly linked via the sentinel node. It can be conceptualized as two singly linked lists formed from the same data items, but in opposite sequential orders.
The two node links allow traversal of the list in either direction. While adding or removing a node in a doubly linked list requires changing more links than the same operations on a singly linked list, the operations are simpler and potentially more efficient (for nodes other than first nodes) because there is no need to keep track of the previous node during traversal or no need to traverse the list to find the previous node, so that its link can be modified.
Read more about Doubly Linked List: Nomenclature and Implementation
Famous quotes containing the words doubly, linked and/or list:
“A man calumniated is doubly injured—first by him who utters the calumny, and then by him who believes it.”
—Herodotus (c. 484–425 B.C.)
“In the dominant Western religious system, the love of God is essentially the same as the belief in God, in God’s existence, God’s justice, God’s love. The love of God is essentially a thought experience. In the Eastern religions and in mysticism, the love of God is an intense feeling experience of oneness, inseparably linked with the expression of this love in every act of living.”
—Erich Fromm (1900–1980)
“We saw the machinery where murderers are now executed. Seven have been executed. The plan is better than the old one. It is quietly done. Only a few, at the most about thirty or forty, can witness [an execution]. It excites nobody outside of the list permitted to attend. I think the time for capital punishment has passed. I would abolish it. But while it lasts this is the best mode.”
—Rutherford Birchard Hayes (1822–1893)