public GridNode Item(int x, int y)
{
GridNode node = new GridNode(x, y);
//Get the index on the y axis
int index = mYList.BinarySearch(node, mComparerY);
if (index < 0) return null;
//Get the x arraylist
ArrayList xList = (ArrayList) mYList[index];
index = xList.BinarySearch(node, mComparerX);
if (index < 0) return null;
return (GridNode) xList[index];
}
public virtual void Add(GridNode node)
{
//Get the index on the y axis
int index = mYList.BinarySearch(node, mComparerY);
//If not found, add a new x list with a new item
if (index < 0)
{
ArrayList xList = new ArrayList();
xList.Add(node);
mYList.Insert(~index, xList); //Insert the node at the correct index which is the bitwise complement
return;
}
//Get the x arraylist
ArrayList x = (ArrayList) mYList[index];
index = x.BinarySearch(node, mComparerX);
if (index < 0)
{
x.Insert(~index, node); //Insert the node at the correct index
}
}
// Push an object onto the PQ
// Returns the index in the list where the object is _now_. This will change when objects are taken from or put onto the PQ.
public int Push(GridNode O)
{
int p = InnerList.Count, p2;
InnerList.Add(O); // E[p] = O
while (true)
{
if (p==0) break;
p2 = (p-1) / 2;
if (OnCompare(p, p2) < 0)
{
SwitchElements(p, p2);
p = p2;
}
else
{
break;
}
}
return p;
}
public void Update(GridNode node)
{
//Get the index of the node into i
int i = InnerList.BinarySearch(node);
if (i < 0) return;
int p = i,pn;
int p1, p2;
while (true)
{
if(p==0) break;
p2 = (p-1)/2;
if(OnCompare(p,p2) < 0)
{
SwitchElements(p,p2);
p = p2;
}
else
{
break;
}
}
if (p < i) return;
while (true)
{
pn = p;
p1 = 2*p+1;
p2 = 2*p+2;
if (InnerList.Count > p1 && OnCompare(p,p1) > 0) p = p1;
if (InnerList.Count > p2 && OnCompare(p,p2) > 0) p = p2;
if(p==pn) break;
SwitchElements(p,pn);
}
}
