public void Pop(int count)
{
if (count == 0)
{
return;
}
for (int i = 0; i < count; i++)
{
head = head.Previous;
}
head.Next = null;
HeadIndex -= count;
if (HeadIndex == -1)
{
root = null;
head = null;
HeadIndex = 0;
}
else
{
ResetPattern();
}
}
private void ResetPattern()
{
matchedStartIndex = 0;
patternStartIndex = 0;
patternStartNode = root;
matchedStartNode = null;
CurrentPattern.Clear();
for (var currentNode = root; currentNode != null; currentNode = currentNode.Next)
{
CurrentPattern.Add(currentNode.Value);
}
MinimizePattern();
}
public T Pop()
{
T value = head.Value;
head = head.Previous;
head.Next = null;
HeadIndex--;
if (HeadIndex == 0)
{
root = null;
}
ResetPattern();
return(value);
}
public bool Push(T value)
{
PatternStackNode <T> node = new PatternStackNode <T>(null, head, value);
if (head != null)
{
head.Next = node;
}
else
{
root = node;
HeadIndex = -1;
}
head = node;
HeadIndex++;
return(AddToPattern(head));
}
/// <summary>
/// Shrinks pattern until it finds a match or becomes empty
/// </summary>
/// <returns>
/// Returns false if pattern becomes empty
/// </returns>
private bool MinimizePattern()
{
while (patternStartIndex != HeadIndex + 1)
{
if (FindMatch())
{
return(true);
}
CurrentPattern.RemoveAt(0);
patternStartIndex++;
patternStartNode = patternStartNode.Next;
}
matchedStartIndex = 0;
patternStartIndex = 0;
matchedStartNode = null;
patternStartNode = null;
return(false);
}
/// <summary>
/// Adds a new node to the current pattern and revalidates
/// </summary>
/// <returns>
/// Returns true if pattern is matched fully and repetition is hit
/// </returns>
private bool AddToPattern(PatternStackNode <T> node)
{
CurrentPattern.Add(node.Value);
if (patternStartNode == null)
{
patternStartNode = node;
patternStartIndex = HeadIndex;
}
if (matchedStartNode != null)
{
if (CheckIfMatches())
{
if (PatternFull())
{
return(true);
}
return(false);
}
}
if (FindMatch())
{
if (PatternFull())
{
return(true);
}
return(false);
}
if (MinimizePattern())
{
if (PatternFull())
{
return(true);
}
}
return(false);
}
/// <summary>
/// Tries to find a match for the current Pattern
/// </summary>
/// <returns>
/// Returns true if pattern is matched by match nodes.
/// Note: Does not require the match to be a full match (repetition might not be hit)
/// </returns>
private bool FindMatch()
{
if (patternStartIndex == 0)
{
return(false);
}
var currentNode = patternStartNode.Previous;
for (int i = patternStartIndex - 1; i >= 0; i--)
{
matchedStartIndex = i;
matchedStartNode = currentNode;
if (CheckIfMatches())
{
return(true);
}
currentNode = currentNode.Previous;
}
matchedStartNode = null;
matchedStartIndex = 0;
return(false);
}
public PatternStackNode(PatternStackNode <T> Next, PatternStackNode <T> Previous, T Value)
{
this.Next = Next;
this.Previous = Previous;
this.Value = Value;
}
