//TODO: quick sort and take the kth element
public int FindKthLargest_HeapImplementation(int[] nums, int k)
{
//max-heapify and extract the first k numbers
MaxHeap <int> maxHeap = new MaxHeap <int>(nums.ToList());
for (int i = 0; i < k - 1; i++)
{
maxHeap.ExtractMax();
}
return(maxHeap.ExtractMax());
}
public static T[] Sort(T[] input)
{
var heap = new MaxHeap <T>(input.Length, input);
for (int i = input.Length - 1; i >= 1; i--)
{
var tmp = heap.array[0];
heap.array[0] = heap.array[i];
heap.heapSize--;
heap.Heapify(0);
}
return(heap.array);
}
// usage
public static int minSum(List <int> num, int k)
{
MaxHeap heap = new MaxHeap();
// fill the heap.
heap.Heapify(num, num.Count);
HeapNode data;
for (int i = 0; i < k; i++)
{
data = heap.GetMax();
int newValue = (int)Math.Ceiling(num[data.Index] / 2.0);
num[data.Index] = newValue;
heap.ChangeMax(newValue);
}
return(num.Sum());
}
public static int[] HeapSort(int[] inputArray)
{
var tempArray = new int[inputArray.Length];
tempArray = inputArray.Select(item => item).ToArray();
var heap = new MaxHeap <int>();
foreach (var item in tempArray)
{
heap.Add(item);
}
for (var i = tempArray.Length - 1; i >= 0; i--)
{
tempArray[i] = heap.RemoveMaxAndReturnItsValue();
}
return(tempArray);
}
private static void MaxHeapTest()
{
var intHeap = new MaxHeap <int>();
intHeap.Add(24);
intHeap.Add(37);
intHeap.Add(17);
intHeap.Add(28);
intHeap.Add(31);
intHeap.Add(29);
intHeap.Add(15);
intHeap.Add(12);
intHeap.Add(20);
intHeap.Add(40);
WriteHeapToConsole(intHeap);
while (intHeap.Count > 0)
{
intHeap.RemoveMaxAndReturnItsValue();
WriteHeapToConsole(intHeap);
}
}
public int MaximumBWUsingHeap(Graph graph, int source, int destination)
{
elapsed = 0;
var watch = Stopwatch.StartNew();
Dad = new int[graph.NumberOfVertices];
Bandwidth = new int[graph.NumberOfVertices];
Status = new int[graph.NumberOfVertices];
int vertices = graph.NumberOfVertices;
MaxHeap maxHeap = new MaxHeap(graph.NumberOfVertices);
try
{
for (int i = 0; i < vertices; i++)
{
Status[i] = (int)Enum.VertexStatus.UNSEEN;
}
Status[source] = (int)Enum.VertexStatus.INTREE;
// Console.Write("Path : " +source + " ");
Dad[source] = 0;
Bandwidth[source] = 0;
List <Edge> adjacentEdges = graph.Adjacent[source];
foreach (Edge edge in adjacentEdges)
{
int v = edge.GetAdjacentVertex(source);
Status[v] = (int)Enum.VertexStatus.FRINGE;
Dad[v] = source;
Bandwidth[v] = edge.Weight;
maxHeap.Insert(v, Bandwidth[v]);
}
int count = 0;
while (!maxHeap.IsEmpty()) // while there are fringes
{
count++;
int maximumIndex = -1;
maximumIndex = maxHeap.ExtractMaximum();
Status[maximumIndex] = (int)Enum.VertexStatus.INTREE;
// Console.Write(maximumIndex + " ");
List <Edge> verticesTowardsMax = graph.Adjacent[maximumIndex];
foreach (Edge edge in verticesTowardsMax)
{
int v = edge.GetAdjacentVertex(maximumIndex);
if (Status[v] == (int)Enum.VertexStatus.UNSEEN)
{
Dad[v] = maximumIndex;
Status[v] = (int)Enum.VertexStatus.FRINGE;
Bandwidth[v] = Math.Min(Bandwidth[maximumIndex], edge.Weight);
maxHeap.Insert(v, Bandwidth[v]);
}
else if (Status[v] == (int)Enum.VertexStatus.FRINGE && Bandwidth[v] < Math.Min(Bandwidth[maximumIndex], edge.Weight))
{
Dad[v] = maximumIndex;
Bandwidth[v] = Math.Min(Bandwidth[maximumIndex], edge.Weight);
maxHeap.Modify(v, Bandwidth[v]);
}
}
}
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
throw ex;
}
watch.Stop();
elapsed = watch.Elapsed.TotalSeconds;
Console.WriteLine("Dijkstra : Time to calculate maximum bandwidth using Heap = " + elapsed);
return(Bandwidth[destination]);
}