public HuffmanTree(Dictionary <int, int> counts) //O(N)
{
PriorityQueue <HuffmanNode> priorityQueue = new PriorityQueue <HuffmanNode>();
foreach (KeyValuePair <int, int> kvp in counts)
{
HuffmanNode N = new HuffmanNode();
N.Value = kvp.Key;
N.Count = kvp.Value;
priorityQueue.Enqueue(N, kvp.Value);
}
while (priorityQueue.Count > 1)
{
HuffmanNode n1 = priorityQueue.Dequeue();
HuffmanNode n2 = priorityQueue.Dequeue();
HuffmanNode n3 = new HuffmanNode();
n3.Left = n2; n3.Right = n1; n3.Count = n1.Count + n2.Count;
priorityQueue.Enqueue(n3, n3.Count);
}
root = priorityQueue.Dequeue();
}