/// <summary>
/// lets the value at arr[i] swim up so that themaxheap obeys the max-heap property.
/// </summary>
/// <param name="i"></param>
public void Swimup(int i)
{
while (i > 0 && arr[Parent(i)].CompareTo(arr[i]) < 0)
{
SortCommons <T> .Exchange(arr, i, Parent(i));
i = Parent(i);
}
}
/// <summary>
/// return and remove the max one
/// </summary>
/// <returns></returns>
public T Pop()
{
if (IsEmpty())
{
throw new Exception("heap is empty");
}
T tmp = arr[0];
SortCommons <T> .Exchange(arr, 0, heapSize - 1);
heapSize--;
Sink(0);
if (heapSize != 0 && arr.Length / heapSize > 2 && arr.Length / 2 >= 4)
{
Array.Resize(ref arr, arr.Length / 2);
}
return(tmp);
}
/// <summary>
/// lets the value at arr[i] “float down” in the max-heap so that the subtree rooted at index i obeys the max-heap property.
/// it runs at O(lgn)
/// </summary>
/// <param name="i"></param>
public void Sink(int i)
{
int left = Left(i);
int right = Right(i);
int max = i;
if (left < heapSize && arr[left].CompareTo(arr[max]) > 0)
{
max = left;
}
if (right < heapSize && arr[right].CompareTo(arr[max]) > 0)
{
max = right;
}
if (max != i)
{
SortCommons <T> .Exchange(arr, max, i);
Sink(max);
}
}