public override void DeleteMin()
{
#if VERBOSE
Console.WriteLine("Current min ({0}:{1}:{2}) >>",
_roots.Count(r => r != null),
_consolidateRoots == null ? 0 : _consolidateRoots.GetSiblings().Count(),
Count);
Console.WriteLine(_minNode == null ? string.Empty : _minNode.ToString(_traversalActions));
Console.WriteLine(">> Delete-Min");
#endif
LastConsolidateDepth = 0;
if (Count == 0)
{
return;
}
if (Count == 1)
{
Debug.Assert(_minNode.FirstChild == null);
Debug.Assert(_minNode.LeftSibling == _minNode.RightSibling && _minNode.RightSibling == _minNode);
_minNode.Dispose();
_minNode = null;
_consolidateRoots = null;
Debug.Assert(_roots.Count == 1);
_roots.Stretch(0);
Count = 0;
return;
}
Debug.Assert(_minNode != null);
Debug.Assert(_minNode.LeftSibling != null && _minNode.RightSibling != null);
// Remove min from its list and gut it
var children = (HeapNode)_minNode.FirstChild;
// Cut the minimum from roots
if (_roots[_minNode.Order] == _minNode)
{
_roots[_minNode.Order] = null;
}
else
{
// MinNode must be among nodes to be consolidated
Debug.Assert(_consolidateRoots.GetSiblings().Contains(_minNode));
if (_minNode.RightSibling == _minNode)
{
_consolidateRoots = null; // It is the only consolidated root -- remove it
}
else
{
_consolidateRoots = (HeapNode)_minNode.RightSibling;
}
}
// Remove from family -- preserves children
_minNode.CutFromFamily();
_minNode.Dispose();
_minNode = null;
Count--;
// Make min's children into roots
if (children != null)
{
Debug.Assert(children.LeftSibling != null && children.RightSibling != null);
children.Parent = null;
AddForConsolidation(children);
}
// Combine roots and find the new minimum
Consolidate();
}