在计算机科学中, 一个 链表 是数据元素的线性集合, 元素的线性顺序不是由它们在内存中的物理位置给出的。 相反, 每个元素指向下一个元素。它是由一组节点组成的数据结构,这些节点一起,表示序列。
在最简单的形式下，每个节点由数据和到序列中下一个节点的引用(换句话说，链接)组成。这种结构允许在迭代期间有效地从序列中的任何位置插入或删除元素。
更复杂的变体添加额外的链接，允许有效地插入或删除任意元素引用。链表的一个缺点是访问时间是线性的(而且难以管道化)。
更快的访问，如随机访问，是不可行的。与链表相比，数组具有更好的缓存位置。
Add(value)
Pre: value is the value to add to the list
Post: value has been placed at the tail of the list
n ← node(value)
if head = ø
head ← n
tail ← n
else
tail.next ← n
tail ← n
end if
end Add
Prepend(value)
Pre: value is the value to add to the list
Post: value has been placed at the head of the list
n ← node(value)
n.next ← head
head ← n
if tail = ø
tail ← n
end
end Prepend
Contains(head, value)
Pre: head is the head node in the list
value is the value to search for
Post: the item is either in the linked list, true; otherwise false
n ← head
while n != ø and n.value != value
n ← n.next
end while
if n = ø
return false
end if
return true
end Contains
Remove(head, value)
Pre: head is the head node in the list
value is the value to remove from the list
Post: value is removed from the list, true, otherwise false
if head = ø
return false
end if
n ← head
if n.value = value
if head = tail
head ← ø
tail ← ø
else
head ← head.next
end if
return true
end if
while n.next != ø and n.next.value != value
n ← n.next
end while
if n.next != ø
if n.next = tail
tail ← n
end if
n.next ← n.next.next
return true
end if
return false
end Remove
Traverse(head)
Pre: head is the head node in the list
Post: the items in the list have been traversed
n ← head
while n != 0
yield n.value
n ← n.next
end while
end Traverse
ReverseTraversal(head, tail)
Pre: head and tail belong to the same list
Post: the items in the list have been traversed in reverse order
if tail != ø
curr ← tail
while curr != head
prev ← head
while prev.next != curr
prev ← prev.next
end while
yield curr.value
curr ← prev
end while
yeild curr.value
end if
end ReverseTraversal
| Access | Search | Insertion | Deletion |
|---|---|---|---|
| O(n) | O(n) | O(1) | O(1) |
O(n)