Sort (Comparison<T> comparison)
stable, in-place sort (mergesort) of a LinkedList<T>. LinkedList<T> has O(1) insertion, great for large lists. this lets you sort it.
Source
//
// Summary:
// Sorts the elements in the entire System.Collections.Generic.LinkedList<T> using
// the default comparer.
//
public static void Sort<T> (this LinkedList<T> @this)
{
@this.Sort (Comparer<T>.Default.Compare);
}
//
// Summary:
// Sorts the elements in the entire System.Collections.Generic.LinkedList<T> using
// the specified comparer.
//
// Parameters:
// comparer:
// The System.Collections.Generic.IComparer<T> implementation to use when comparing
// elements, or null to use the default comparer System.Collections.Generic.Comparer<T>.Default.
//
public static void Sort<T> (this LinkedList<T> @this, IComparer<T> comparer)
{
if (comparer == null)
comparer = Comparer<T>.Default;
@this.Sort (comparer.Compare);
}
//
// Summary:
// Sorts the elements in the entire System.Collections.Generic.LinkedList<T> using
// the specified System.Comparison<T>.
//
// Parameters:
// comparison:
// The System.Comparison<T> to use when comparing elements.
//
// Exceptions:
// System.ArgumentNullException:
// comparison is null.
//
public static void Sort<T> (this LinkedList<T> @this, Comparison<T> comparison)
{
if (@this == null)
throw new NullReferenceException ();
if (comparison == null)
throw new ArgumentNullException ("comparison");
int count = @this.Count;
if (count <= 1)
return;
// merge pairs of lists of doubling size
for (int mergeLength = 1; mergeLength < count; mergeLength *= 2)
{
LinkedListNode<T> mergedTail = null;
LinkedListNode<T> head2;
for (LinkedListNode<T> head1 = @this.First; head1 != null; head1 = head2)
{
// skip over the 1st part to the start 2nd
head2 = head1;
int length1;
for (length1 = 0; length1 < mergeLength && head2 != null; ++length1)
head2 = head2.Next;
// assume we have a full-length 2nd part
int length2 = mergeLength;
// while we still have items to merge
while (length1 > 0 || (length2 > 0 && head2 != null))
{
LinkedListNode<T> next;
// determine which part the next item comes from
if (length1 != 0 && !(length2 != 0 && head2 != null && comparison (head1.Value, head2.Value) > 0))
{
// take item from 1st part
Debug.Assert (head1 != null);
next = head1;
head1 = head1.Next;
Debug.Assert (length1 > 0);
--length1;
}
else
{
// take item from 2nd part
Debug.Assert (head2 != null);
next = head2;
head2 = head2.Next;
Debug.Assert (length2 > 0);
--length2;
}
// append the next item to the merged list
if (mergedTail == null)
{
// start a new merged list at the front of the source list
if (@this.First != next) // check for no-op
{
@this.Remove (next);
@this.AddFirst (next);
}
}
else if (mergedTail.Next != next) // check for no-op
{
@this.Remove (next);
@this.AddAfter (mergedTail, next);
}
// advance the merged tail
mergedTail = next;
}
}
}
}
Example
LinkedList<int> list = new LinkedList<int> (Enumerable.Range (0, 100).Reverse ());
list.Sort ();
Console.WriteLine (string.Join (", ", from l in list select l.ToString ()));
Author: Piers Haken
Submitted on: 30 okt. 2010
Language: C#
Type: System.Collections.Generic.LinkedList<T>
Views: 5534