/***************************************************************************
* Helper functions to restore the heap invariant.
***************************************************************************/
private void swim(int k)
{
while (k > 1 && OrderHelper.Greater <Key>(pq[k / 2], pq[k]))
{
OrderHelper.Exch(pq, k, k / 2);
k = k / 2;
}
}
private void sink(int k)
{
while (2 * k <= N)
{
int j = 2 * k;
if (j < N && OrderHelper.Greater <Key>(pq[j], pq[j + 1]))
{
j++;
}
if (!OrderHelper.Greater <Key>(pq[k], pq[j]))
{
break;
}
OrderHelper.Exch(pq, k, j);
k = j;
}
}
// is subtree of pq[1..N] rooted at k a min heap?
private bool isMinHeap(int k)
{
if (k > N)
{
return(true);
}
int left = 2 * k, right = 2 * k + 1;
if (left <= N && OrderHelper.Greater <Key>(pq[k], pq[left]))
{
return(false);
}
if (right <= N && OrderHelper.Greater <Key>(pq[k], pq[right]))
{
return(false);
}
return(isMinHeap(left) && isMinHeap(right));
}