public static bool Delete <T>(this Skiplist <T> skiplist, T key)
{
if (skiplist.Head == null)
{
return(false);
}
if (skiplist.Head.Down == null && skiplist.AreEqual(skiplist.Head.Key, key))
{
return(TryRemoveCurrentHead(skiplist, key));
}
var keyFound =
skiplist.Find(
key: key,
pathAction: node => HandlePathToDeletionPoint(node, key, skiplist.MinimumGapSize, skiplist.AreEqual),
origin: skiplist.Head.Down);
if (skiplist.Head.Down.LengthOfList() <= 1)
{
skiplist.Head = skiplist.Head.Down;
skiplist.Head.Up = null;
}
return(keyFound);
}
public static bool Find <T>(
this Skiplist <T> skiplist,
T key,
INode <T> origin = null,
Action <INode <T> > pathAction = null)
{
var nodeOfKey = skiplist.FetchNode(key, origin, pathAction);
return(skiplist.AreEqual(nodeOfKey.Key, key));
}
private static bool TryRemoveCurrentHead <T>(Skiplist <T> skiplist, T key)
{
if (skiplist.Head.Right == skiplist.Head && skiplist.AreEqual(skiplist.Head.Key, key))
{
skiplist.Head = null;
return(true);
}
else
{
return(false);
}
}