public void Enqueue(PQueueItem item)
{
int index = numElem;
if (item == null || index >= 39)
{
return; // first element stored at 1
}
while (index > 1 && item.Priority < pQ[index / 2].Priority)
{
pQ[index] = pQ[index / 2];
index = index / 2;
}
pQ[index] = item;
numElem++;
}
public PQueueItem Dequeue()
{
if (pQ[1] == null || numElem <= 1)
{
return(null);
}
PQueueItem itemtoBeReturned = pQ[1];
PQueueItem lastElement = pQ[--numElem];
int childIndex;
int i;
//IMP: this for loop is critical! see i being init to childIndex! (i tried while loop and failed miserably)
for (i = 1; i * 2 <= numElem; i = childIndex)
{
//find smaller child
childIndex = i * 2;
if (childIndex != numElem)
{
if (pQ[childIndex + 1].Priority < pQ[childIndex].Priority)
{
childIndex++;
}
}
//percolate one level
if (lastElement.Priority > pQ[childIndex].Priority)
{
pQ[i] = pQ[childIndex];
}
else
{
break;
}
}
pQ[i] = lastElement;
pQ[numElem] = null;
return(itemtoBeReturned);
}
private void KruskalGraphInit()
{
//populate graph - TODO
PQueueItem a = new PQueueItem(1, new int[2] {
1, 2
});
PQueueItem b = new PQueueItem(1, new int[2] {
2, 3
});
PQueueItem c = new PQueueItem(1, new int[2] {
3, 4
});
PQueueItem d = new PQueueItem(1, new int[2] {
4, 5
});
PQueueItem e = new PQueueItem(4, new int[2] {
2, 5
});
PQueueItem f = new PQueueItem(3, new int[2] {
3, 5
});
PQueueItem g = new PQueueItem(6, new int[2] {
1, 4
});
PQueueItem h = new PQueueItem(5, new int[2] {
1, 5
});
GraphPQ.Enqueue(a);
GraphPQ.Enqueue(b);
GraphPQ.Enqueue(c);
GraphPQ.Enqueue(d);
GraphPQ.Enqueue(e);
GraphPQ.Enqueue(f);
GraphPQ.Enqueue(g);
GraphPQ.Enqueue(h);
}