public void computeMST(GraphAdjList adjList,
int start)
{
initialize(adjList);
Q.updatePriority(new HeapClass()
{
data = start,
priority = 0
});
while (Q.count() != 0)
{
HeapClass priorityElement = Q.getMax();
foreach (var v in adjList.getAdj(priorityElement.data))
{
if (Q.contains(v.Item1) && -1 * v.Item2 > Q.getPriority(v.Item1))
{
Q.updatePriority(new HeapClass()
{
data = v.Item1,
priority = -1 * v.Item2
});
parents[v.Item1] = priorityElement.data;
}
}
}
Console.WriteLine("\nvertex\tparent");
for (int i = 0; i < V; i++)
{
Console.WriteLine("\n" + i + "\t\t" + parents[i]);
}
}
void swap(int a, int b)
{
HeapClass temp = arr[a];
arr[a] = arr[b];
arr[b] = temp;
}
public void computeShortestPaths(GraphAdjList adjList,
int source)
{
initializeSingleSource(source);
extractEdges(adjList);
for (int i = 0; i < V; i++)
{
Q.insertHeap(new HeapClass()
{
data = i, priority = distances[i]
});
}
while (Q.count() != 0)
{
HeapClass elem = Q.getMax();
foreach (var v in adjList.getAdj(elem.data))
{
relax(elem.data, v.Item1, v.Item2);
}
}
Console.WriteLine("\nvertex\tparent\tdistance");
for (int i = 0; i < V; i++)
{
Console.WriteLine(i + "\t" + parents[i] + "\t" + (-1 * distances[i]).ToString());
}
}
public void updatePriority(HeapClass elem)
{
int elemIndex = Array.IndexOf(arr, arr.Where(k => k.data == elem.data).FirstOrDefault());
arr[elemIndex].priority = elem.priority;
while (elemIndex != 0 && arr[parent(elemIndex)].priority < arr[elemIndex].priority)
{
swap(elemIndex, parent(elemIndex));
elemIndex = parent(elemIndex);
}
}
public void insertHeap(HeapClass data)
{
if (heapCurrentFillLevel == heapSize)
{
throw new Exception("heap size exceeded");
}
heapCurrentFillLevel++;
int currentIndex = heapCurrentFillLevel - 1;
arr[currentIndex] = data;
while (currentIndex != 0 && arr[parent(currentIndex)].priority < arr[currentIndex].priority)
{
swap(currentIndex, parent(currentIndex));
currentIndex = parent(currentIndex);
}
}
public HeapClass getMax()
{
if (heapCurrentFillLevel <= 0)
{
throw new Exception("heapsize less than 0");
}
if (heapCurrentFillLevel == 1)
{
heapCurrentFillLevel -= 1;
return(arr[heapCurrentFillLevel]);
}
//Console.Write(heapCurrentFillLevel);
HeapClass element = arr[0];
arr[0] = arr[heapCurrentFillLevel - 1];
heapCurrentFillLevel -= 1;
heapify(0);
return(element);
}
