public static bool CheckMarkovTheorem(Code code)
{
OrientedGraph graph = new OrientedGraph();
GraphNode startNode = new GraphNode(String.Empty);
graph.AddNode(startNode);
foreach (var codeword in code.ElementaryCodes.Values)
{
for (int i = 0; i < codeword.Length; i++)
{
string prefix = codeword.Substring(0, i);
string tail = codeword.Substring(i);
List <string> postfixes = new List <string>();
Queue <string> tails = new Queue <string>();
tails.Enqueue(tail);
while (tails.Count > 0)
{
string currentTail = tails.Dequeue();
foreach (var middleWord in code.ElementaryCodes.Values)
{
if (middleWord.Length <= currentTail.Length && codeword != middleWord &&
currentTail.Substring(0, middleWord.Length) == middleWord)
{
string newTail = currentTail.Substring(middleWord.Length);
tails.Enqueue(newTail);
postfixes.Add(newTail);
}
}
}
if (postfixes.Count == 0)
{
continue;
}
GraphNode prefixNode = graph.GetNode(prefix);
if (prefixNode == null)
{
prefixNode = new GraphNode(prefix);
graph.AddNode(prefixNode);
}
foreach (var postfix in postfixes)
{
if (postfix != codeword)
{
GraphNode postfixNode = graph.GetNode(postfix);
if (postfixNode == null)
{
postfixNode = new GraphNode(postfix);
graph.AddNode(postfixNode);
}
prefixNode.Connections.Add(postfixNode);
}
}
}
}
return(!graph.CycleWithNodeExists(startNode));
}
/// <summary>
/// fields dependencies graph
/// </summary>
private OrientedGraph CreateFieldsGraph(Dictionary <String, FieldInfo> fields)
{
OrientedGraph FieldsGraph = new OrientedGraph(); // граф зависимости полей сделки
// add graph nodes
foreach (var field in fields.Keys)
{
FieldsGraph.AddNode(field);
// add graph transitions
foreach (var fieldList in fields.Values)
{
// nH. Пропустить ребра, направленные в поле, которое изменилось.
//if (startField != null && !startField.Equals(field.Name, StringComparison.Ordinal))
foreach (var param in fieldList.lParamInfo.Where(p => !p.IsDeleted))
{
if (param != null && FieldsGraph.ContainsNode(param.FieldName))
{
FieldsGraph.AddInTrans(field, param.FieldName);
}
}
}
}
return(FieldsGraph);
}
public static FrequencyCode GetOptimalCode(string alphabet, Dictionary <char, double> frequencyList)
{
int q = frequencyList.Count % (alphabet.Length - 1);
if (q == 0)
{
q = alphabet.Length - 1;
}
if (q == 1)
{
q = alphabet.Length;
}
List <NodeContent> looseVertices = new List <NodeContent>();
OrientedGraph graph = new OrientedGraph();
foreach (var item in frequencyList)
{
NodeContent content = new NodeContent(item.Key, item.Value);
AddToListWithSort(looseVertices, content);
graph.AddNode(new GraphNode(content));
}
while (looseVertices.Count > 1)
{
NodeContent newContent = new NodeContent();
GraphNode newNode = new GraphNode(newContent);
for (int i = 0; i < q; i++)
{
NodeContent content = looseVertices[0];
newContent.Frequency += content.Frequency;
GraphNode node = graph.GetNode(content);
newNode.Connections.Add(node);
looseVertices.RemoveAt(0);
}
AddToListWithSort(looseVertices, newContent);
graph.AddNode(newNode);
q = alphabet.Length;
}
FrequencyCode code = new FrequencyCode();
Queue <GraphNode> broadSearchQueue = new Queue <GraphNode>();
broadSearchQueue.Enqueue(graph.GetNode(looseVertices[0]));
while (broadSearchQueue.Count > 0)
{
GraphNode node = broadSearchQueue.Dequeue();
NodeContent content = (NodeContent)node.NodeContent;
if (node.Connections.Count == 0)
{
code.Set(content.Symbol, content.Code, content.Frequency);
}
else
{
for (int i = 0; i < node.Connections.Count; i++)
{
NodeContent childContent = (NodeContent)node.Connections[i].NodeContent;
childContent.Code = content.Code + alphabet[i];
broadSearchQueue.Enqueue(node.Connections[i]);
}
}
}
return(code);
}
