public void HeapifiyNodeDown(int index)
{
int tempIndex;
if (index * 2 + 1 < heap.Length)
{
if (heap[index * 2 + 1] != null)
{
tempIndex = heap[index * 2].Priority > heap[index * 2 + 1].Priority ? index * 2 : index * 2 + 1;
}
else
{
tempIndex = index * 2;
}
if (heap[tempIndex] != null)
{
if (heap[index].Priority < heap[tempIndex].Priority)
{
//swap nodes
PQNode tempNode = heap[index];
heap[index] = heap[tempIndex];
heap[tempIndex] = tempNode;
HeapifiyNodeDown(tempIndex);
}
}
}
}
public void HeapifyDown(int pos)
{
if (pos <= Count / 2)
{
if (_holdthis[pos * 2] != null && _holdthis[(pos * 2) + 1] == null)
{
if (_holdthis[pos].Priority < _holdthis[pos * 2].Priority)
{
PQNode temp = _holdthis[pos * 2];
_holdthis[pos * 2] = _holdthis[pos];
_holdthis[pos] = temp;
HeapifyDown(pos * 2);
}
}
else if (_holdthis[pos * 2] != null && _holdthis[(pos * 2) + 1] != null && _holdthis[pos * 2].Priority > _holdthis[(pos * 2) + 1].Priority)
{
PQNode temp = _holdthis[pos * 2];
_holdthis[pos * 2] = _holdthis[pos];
_holdthis[pos] = temp;
HeapifyDown(pos * 2);
}
else
{
PQNode temp = _holdthis[(pos * 2) + 1];
_holdthis[(pos * 2) + 1] = _holdthis[pos];
_holdthis[pos] = temp;
HeapifyDown((pos * 2) + 1);
}
}
}
public void Enqueue(int priority, int value)
{
PQNode pQNode = new PQNode()
{
Priority = priority, Value = value
};
if (root == null)
{
root = pQNode;
}
else
{
PQNode tempPQNode = root;
tempPQNode = AddPQNode(tempPQNode);
tempPQNode.NextNode = pQNode;
Count++;
int counter = Count - 1;
while (counter > 0)
{
int i = (counter - 1) / 2;
if (Find(counter).Value.CompareTo(Find(i).Value) >= 0)
{
break;
}
SwitchPQNodes(counter, i);
counter = i;
}
}
}
private PQNode AddPQNode(PQNode pQNode)
{
while (pQNode.NextNode != null)
{
pQNode = pQNode.NextNode;
}
return(pQNode);
}
/**Using heapsort, produce and return an array of PQNode instances sorted in non-decreasing order of priority.
* Despite the typical convention of ignoring index 0 of the backing array, the array you return from this method
* should start at 0 and continue to index n-1 (like a typical array in Java or C#)
**/
public PQNode[] ToSortedArray()
{
PQNode[] outputArray = new PQNode[Count];
Array.Copy(_holdthis, 1, outputArray, 0, Count);
HeapSort(outputArray);
return(outputArray);
}
public PQNode Dequeue()
{
PQNode pQNode = root;
root = root.NextNode;
root.PrevNode = null;
Count--;
return(root);
}
private PQNode Find(int index)
{
PQNode temp = root;
for (int i = 0; i < index; i++)
{
temp = temp.NextNode;
}
return(temp);
}
public PQNode[] ToSortedArray()
{
PQNode[] array = new PQNode[Count];
int i = 0;
while (Count > 0)
{
array[i] = Dequeue();
i++;
}
return(array);
}
public int CompareTo(object obj)
{
PQNode <T> other = obj as PQNode <T>;
int compareValue = Priority.CompareTo(other.Priority);
if (compareValue == 0)
{
// priority is the same, compare by their value
compareValue = Value.CompareTo(other.Value);
}
return(compareValue);
}
public override string ToString()
{
StringBuilder stringBuilder = new StringBuilder();
PQNode pQNode = root;
while (pQNode.NextNode != null)
{
stringBuilder.Append(pQNode.Priority + ":" + pQNode.Value + ", ");
pQNode = pQNode.NextNode;
}
return(stringBuilder.ToString());
}
//Removes the root node of the queue and returns it, adjusts the count, and heapifies as needed.
public PQNode Dequeue()
{
PQNode temp = _holdthis[1];
_holdthis[1] = _holdthis[Count];
_holdthis[Count] = null;
Count--;
HeapifyDown(1);
return(temp);
}
public override string ToString()
{
StringBuilder sb = new StringBuilder();
for (int j = 0; j < Count; ++j)
{
PQNode <T> node = Queue.Values[j];
sb.Append(node + ", ");
}
string str = sb.ToString().Trim().TrimEnd(',');
return(str);
}
public PQNode Dequeue()
{
PQNode tempNode = null;
if (Count >= 1)
{
tempNode = heap[1];
heap[1] = heap[Count];
heap[Count] = null;
Count--;
HeapifiyNodeDown(1);
}
return(tempNode);
}
public void HeapifiyNodeUp(int index)
{
PQNode parent = heap[index / 2];
if (parent != null && heap[index].Priority > parent.Priority)
{
//swap parent with node
heap[index / 2] = heap[index];
heap[index] = parent;
if (index / 2 != 0)
{
HeapifiyNodeUp(index / 2);
}
}
}
private void SwitchPQNodes(int firstIndex, int secondIndex)
{
PQNode firstNode = Find(firstIndex);
PQNode secondNode = Find(secondIndex);
PQNode tempNode = firstNode;
firstNode.NextNode = secondNode.NextNode;
firstNode.PrevNode = secondNode.PrevNode;
firstNode.Priority = secondNode.Priority;
secondNode.NextNode = tempNode.NextNode;
secondNode.PrevNode = tempNode.PrevNode;
secondNode.Priority = tempNode.Priority;
}
private void HeapifyUp(int pos)
{
if (pos > 1)
{
int parentPos = (pos) / 2;
if (_holdthis[pos].Priority > _holdthis[parentPos].Priority)
{
PQNode temp = _holdthis[parentPos];
_holdthis[parentPos] = _holdthis[pos];
_holdthis[pos] = temp;
HeapifyUp(parentPos);
}
}
}
private void HeapSort(PQNode[] a)
{
int count = a.Length;
int end = count - 1;
while (end > 0)
{
//swap max value of the heap with the last element of the heap
PQNode tmp = a[end];
a[end] = a[0];
a[0] = tmp;
//put the heap back in max-heap order
Heapify(a, end - 1);
//decrease size of the heap so that the previous max value will stay in its new place
end--;
}
}
public void Enqueue(int priority, int value)
{
Count++;
if (Count > heap.Length - 1)
{
PQNode[] tempHeap = new PQNode[heap.Length * 2];
heap.CopyTo(tempHeap, 0);
heap = tempHeap;
}
PQNode tempNode = new PQNode()
{
Value = value, Priority = priority
};
heap[Count] = tempNode;
HeapifiyNodeUp(Count);
}
/** Takes in the priority and value as parameters.Creates a new PQNode with this value and adds the node to the queue,
* adjusts the count, and heapifies as needed. When heapifying, a child node with equal priority to its parent does NOT
* promote and the heapifying of that particular child node stops.
* 1. ignore zero
* 2. priority matters
* 3. p = n , left = 2n, right = 2n + 1
**/
public void Enqueue(int priority, int value)
{
Count++;
PQNode addThis = new PQNode(priority, value);
if (Count == _holdthis.Length)
{
PQNode[] doubleHold = new PQNode[_holdthis.Length * 2];
Array.Copy(_holdthis, 0, doubleHold, 0, Count);
_holdthis = doubleHold;
}
_holdthis[Count] = addThis;
if (Count > 1)
{
HeapifyUp(Count);
}
}
public void Heapify(PQNode[] a, int end)
{
int root = 0;
while ((root * 2) + 1 <= end)
{
int child = root * 2 + 1;
if (child + 1 <= end && a[child].Priority < a[child + 1].Priority)
{
child = child + 1;
}
if (a[root].Priority < a[child].Priority)
{
PQNode tmp = a[root];
a[root] = a[child];
a[child] = tmp;
root = child;
}
else
{
return;
}
}
}
/// <summary>
/// Creates a PQNode with the specified priority and value
/// and adds it to this Queue. PQNodes with the highest
/// priority will be added to the front of this Queue.
/// </summary>
/// <param name="priority">priority level</param>
/// <param name="value">value</param>
public void Enqueue(int priority, T value)
{
PQNode <T> nodeToAdd = new PQNode <T>(priority, value);
Queue.Insert(nodeToAdd);
}
/// <summary>
/// Removes the first PQNode in this queue, which has the
/// highest priority.
/// </summary>
/// <returns>PQNode that we removed</returns>
public PQNode <T> Dequeue()
{
PQNode <T> nodeToRemove = Queue.RemoveMax();
return(nodeToRemove);
}
/// <summary>
/// Returns but doesn't remove the first PQNode in this queue,
/// which has the highest priority.
/// </summary>
/// <returns>PQNode at the start of this Queue</returns>
public PQNode <T> Peek()
{
PQNode <T> node = Queue.Values[0];
return(node);
}