コード例 #1
0
 static void _ReplaceNode(
     BinarySearchTreeNode <T> node,
     BinarySearchTreeNode <T> replacement
     )
 {
     if (node.parent != null)
     {
         if (node.parent.left == node)
         {
             node.parent.left = replacement;
         }
         else
         {
             node.parent.right = replacement;
         }
     }
     if (replacement != null)
     {
         replacement.parent = node.parent;
     }
 }
コード例 #2
0
        public override object Insert(
            Arc arc,
            IComparer comparer = null
            )
        {
            if (comparer == null)
            {
                comparer = insertComparer;
            }
            if (root == null)
            {
                return(base.Insert(arc));
            }

            // find arc within beachline that intersects w/ new arc
            BinarySearchTreeNode <Arc> intersectingArcNode = (BinarySearchTreeNode <Arc>)base.GetNode(arc, comparer);
            Arc intersectingArc = GetNodeData(intersectingArcNode);
            //Debug.Log("intersectingArcNode: " + intersectingArcNode + " intersectingArc: " + intersectingArc);

            // edge is created between site of new arc and site of intersecting arc
            var edge = new Edge(intersectingArc.site, arc.site);

            // intersecting arc is replaced by three arcs and two breakpoints
            var lowerArc        = intersectingArc;
            var middleArc       = arc;
            var upperArc        = new Arc(intersectingArc.site);
            var lowerBreakpoint = new Breakpoint(lowerArc, middleArc, edge, 0);
            var upperBreakpoint = new Breakpoint(middleArc, upperArc, edge, 1);

            // update breakpoints for each arc
            if (lowerArc.upperBreakpoint != null)
            {
                var oldBreakpoint = lowerArc.upperBreakpoint;
                var newBreakpoint = new Breakpoint(
                    upperArc,
                    oldBreakpoint.upperArc,
                    oldBreakpoint.edge,
                    oldBreakpoint.intersectionIndex);
                upperArc.upperBreakpoint = newBreakpoint;
                if (oldBreakpoint.upperArc != null)
                {
                    oldBreakpoint.upperArc.lowerBreakpoint = newBreakpoint;
                }
            }
            upperArc.lowerBreakpoint  = upperBreakpoint;
            middleArc.upperBreakpoint = upperBreakpoint;
            middleArc.lowerBreakpoint = lowerBreakpoint;
            lowerArc.upperBreakpoint  = lowerBreakpoint;
            //lowerArc.lowerBreakpoint remains intact

            // insert new nodes
            // this means that arc and upperArc are added as new nodes
            // lowerArc is original arc
            // new arc becomes parent of lower/upper arcs
            // create new bst nodes
            var arcNode      = new BinarySearchTreeNode <Arc>(arc);
            var upperArcNode = new BinarySearchTreeNode <Arc>(upperArc);

            // link BST nodes
            // arc node is the new parabola being added and becomes root of 3 node cluster
            arcNode.parent = intersectingArcNode.parent;
            arcNode.left   = intersectingArcNode;
            arcNode.right  = upperArcNode;
            if (arcNode.parent == null)
            {
                root = arcNode;
            }
            else
            {
                if (arcNode.parent.right == intersectingArcNode)
                {
                    arcNode.parent.right = arcNode;
                }
                else
                {
                    arcNode.parent.left = arcNode;
                }
            }

            // upper arc is the new arc split from intersecting arc by new parabola
            // left child is null, right child becomes original arc's right
            upperArcNode.parent = arcNode;
            upperArcNode.right  = intersectingArcNode.right;
            if (upperArcNode.right != null)
            {
                upperArcNode.right.parent = upperArcNode;
            }

            // lower arc is the original intersecting arc node
            // left child remains intact, right is set to null
            intersectingArcNode.parent = arcNode;
            intersectingArcNode.right  = null;

            return(arcNode);
        }