Henry Instructions - NET Data Structure Single List (2)
Han Rui (06/15/2003)
3.4 Find in the linked list according to the index position or data element value
Location in the list is the basis for operation, we define two protected findings in the category:
Protected Overridable Function Findby Index (Byval Index As Integer) AS ListNode
'Look for nodes in the list through index
DIM Tempindex as integer = 0
DIM CURRENT As ListNode = Head.NextNode 'starts from the first node after the head knot
DIM RETURNVALUE As ListNode = Nothing 'Initialization Return Node
DO 'loop lookup
IF index = Tempindex Then
ReturnValue = CURRENT
Else
Current = current.nextNode
Tempindex = 1
END IF
LOOP Until Current Is Nothing or Not ReturnValue Is Nothing
Return ReturnValue
END FUNCTION
Protected Overridable Function FindByValue (Byval Value As Object) AS Integer
'Take the data value to find the index of the node in the list
DIM Tempindex as integer = 0
DIM CURRENT As ListNode = Head.NextNode 'starts from the head knot
DIM RETURNVALUE AS INTEGER = -1 'Initialization Return Value
DO 'loop lookup
IF value.equals (current.data) THEN
ReturnValue = Tempindex
Else
Current = current.nextNode
Tempindex = 1
END IF
Loop unsil current is nothing or returnValue> -1
Return ReturnValue
END FUNCTION
With this basis, we can implement the ILIST interface indexof index method:
Public overridable function indexof (Byval value as object) _
As integer imports ilist.indexof
'Return node index by node data value
Validate (Value) 'First verification value
Return FindByValue (Value) 'Call Protected Finding Method
END FUNCTION
In this way, when we use the list to find an index of a value, we will throw an exception if Value is empty; if not found, it will return -1; find the index position where the data element is returned. Is it similar to ArrayList?
In addition, we also need to implement the Contains function, used to determine if there is a value in the list:
Public Overridable Function Contains (Byval Value As Object)
As Boolean Implements IList.Contains
'Find value values in the list
Validate (Value)
If FindByValue (Value) = -1 ThenreTurn False 'can't find
Else
Return True 'found
END IF
END FUNCTION
3.5 Add Node
In the first quarter above, it is mentioned that there are two cases, add the end of the linked list and insert the index value:
Public Overridable Function Add (Byval Value As Object)
As integer imports ilist.add
Add a node to the linked list
Validate (Value) 'First verification value
TAIL.NEXTNODE = New ListNode (Value) 'points the next node of the existing tailpoint to the new node
Tail = tail.nextnode 'Sets the newly added node to the tailpoint
Version = 1 'Change version number
NodeCount = 1 'Add a chain table count
Return NodeCount - 1 'Returns the tail node index
END FUNCTION
Public overridable subinsert (byval index as integer, _
IMPLEMENTS ILIST.Insert
'Add a node to the specified index
Validate (Index, Value) 'Verify Index and Data Value
DIM TEMPNODE As ListNode = FindbyIndex (Index) 'found an existing node at the index
'Define new nodes, the next node of the new node references the index of index to index
DIM NewNode As ListNode = New ListNode (Value, TempNode)
'Pointing the next node of Index-1 points to the new node
FindbyIndex (Index - 1) .nextNode = NewNode
Version = 1 'Change version number
NodeCount = 1 'Add a chain table count
End Sub
3.6 Delete Node
Protected Overridable Sub Removenode (Byval Node As ListNode, Byval Index As INTEGER)
'Delete node used inside the class
'Delete node method is to reference the next node of its previous junction to the next node
DIM TEMPNODE AS LISTNODE = FindByindex (INDEX - 1) 'found the previous node to delete nodes
TempNode.nextNode = node.nextNode
IF node is tail kil
Tail = TempNode
END IF
Version = 1 'Change version number
NodeCount - = 1 'Reduced Lin Try
End Sub
Public Overridable Sub Remove (Byval Value As Object)
Implements IList.remove
Delete method of "class implementation interface
Validate (Value)
Removeat (FindByValue (Value)
End Sub
Public Overridable Sub Removeat (BYVAL INDEX AS INTEGER) _
Implements ilist.removeat
The method of deleting the index in the interface
Validate (INDEX)
Dim node as listnode = findbyindex (index)
Removenode (Node, INDEX)
End Sub
Public Overridable Sub Clear () IMPLEments IList.Clear
'Empty linked list
Head.nextNode = Nothing
Tail = HEAD
NodeCount = 0
Version = 0
End Sub
From the above three Remove methods, it is actually deleted through the RemoveNode method inside the class, but only provides two interfaces to the user: one is deleted according to the index value, one is by comparing the data element value. delete. Here, you will explain it here, the single-link sheet is not to look forward to the previous junction, so the efficiency of deletion is lower than the bidirectional linked list, which will later mention when the double-linked list will be mentioned.
3.7 replication
Press the data element in the list to start with an index, copy the element to the Array. This method is useful in actual operations:
Public Overridable Sub Copyto (Byval Array As System.Array, _
IMPLEMENTS ILIST.COPYTO
'Start copying the elements to the list from the index of the list
IF array is nothing then
Throw new argumentnullexception ()
Elseif Index <0 THEN
Throw new ArgumentOutofrangeException ("index matte")
Elseif Index> = array.length _
Or (Array.Length - INDEX - 1)> NodeCount_
Or array.rank <> 1 THEN
Throw new argumentexception ()
END IF
DIM CURRENT As ListNode = head.nextNode
DIM position as integer = index
'Cycle replication
While Not Current Is Nothing
Array (position) = current.data
Current = current.nextNode
Position = 1
End while
End Sub
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