/// <summary>
/// Recurcively find all paths from node to finishNode.
/// Deep graph search algorithm is used.
/// </summary>
/// <param name="node">node</param>
private void FindPaths(RoadNode node)
{
if (node == null)
{
return;
}
if (node == finishNode)
{
//if we have reached finish node, remember the current path
pathsFound.Add((RoadPath)currentPath.Clone());
}
else
{
List <RoadNode> neighbours = GetNeighbours(node);
foreach (RoadNode neighbour in neighbours)
{
if (!visitedNodes.Contains(neighbour))
{
visitedNodes.Add(neighbour);
currentPath.Push(neighbour);
FindPaths(neighbour);
visitedNodes.Remove(neighbour);
currentPath.Pop();
}
}
}
}
/// <summary>
/// Find all paths in road graph from start node to finish node
/// </summary>
/// <returns>Found paths</returns>
public List <RoadPath> FindAllPaths()
{
CheckMapErrors(roadMap);
startNode = roadMap.Nodes.Where(n => n.Role == RoadNodeRole.Start).Single();
finishNode = roadMap.Nodes.Where(n => n.Role == RoadNodeRole.Finish).Single();
visitedNodes.Add(startNode);
currentPath.Push(startNode);
FindPaths(startNode);
return(pathsFound);
}
/// <summary>
/// Find all paths in road graph from start node to finish node
/// </summary>
/// <returns>Found paths</returns>
public List<RoadPath> FindAllPaths()
{
CheckMapErrors(roadMap);
startNode = roadMap.Nodes.Where(n => n.Role == RoadNodeRole.Start).Single();
finishNode = roadMap.Nodes.Where(n => n.Role == RoadNodeRole.Finish).Single();
visitedNodes.Add(startNode);
currentPath.Push(startNode);
FindPaths(startNode);
return pathsFound;
}
/// <summary>
/// Get non-crashed nodes connected with the node
/// </summary>
/// <param name="node"></param>
/// <returns>list of neighbour nodes</returns>
private List <RoadNode> GetNeighbours(RoadNode node)
{
if (node == null)
{
return(null);
}
List <RoadNode> neighbours = new List <RoadNode>();
foreach (var link in node.Links)
{
RoadNode neighbourByLink = roadMap.Nodes.Where(n => n.Id == link.RefNodeId).Single();
if (neighbourByLink.State == RoadNodeState.Ok)
{
neighbours.Add(neighbourByLink);
}
}
return(neighbours);
}
/// <summary>
/// Parse source road map XML document
/// </summary>
/// <param name="sourceXml">road map XML document</param>
/// <returns>parsed RoadMap object</returns>
public static RoadMap ParseRoadMapXml(XmlDocument sourceXml)
{
if (sourceXml == null)
{
return(null);
}
RoadMap roadMap = new RoadMap();
if (ValidateSchema(sourceXml))
{
XmlNode graph = sourceXml.SelectNodes("/graph").Item(0);
XmlNodeList nodes = graph.SelectNodes("node");
foreach (XmlNode node in nodes)
{
RoadNodeRole nodeRole = RoadNodeRole.Normal;
if (node.Attributes["role"] != null && node.Attributes["role"].Value == "start")
{
nodeRole = RoadNodeRole.Start;
}
else if (node.Attributes["role"] != null && node.Attributes["role"].Value == "finish")
{
nodeRole = RoadNodeRole.Finish;
}
RoadNodeState nodeState = RoadNodeState.Ok;
if (node.Attributes["status"] != null && node.Attributes["status"].Value == "crash")
{
nodeState = RoadNodeState.Crash;
}
int nodeId = Convert.ToInt32(node.Attributes["id"].Value);
RoadNode roadNode = new RoadNode(nodeId, nodeRole, nodeState);
XmlNodeList links = node.SelectNodes("link");
foreach (XmlNode link in links)
{
int linkRef = Convert.ToInt32(link.Attributes["ref"].Value);
int linkWeight = Convert.ToInt32(link.Attributes["weight"].Value);
RoadLink roadLink = new RoadLink(linkWeight, linkRef);
roadNode.Links.Add(roadLink);
}
roadMap.Nodes.Add(roadNode);
}
}
return(roadMap);
}
/// <summary>
/// Parse source road map XML document
/// </summary>
/// <param name="sourceXml">road map XML document</param>
/// <returns>parsed RoadMap object</returns>
public static RoadMap ParseRoadMapXml(XmlDocument sourceXml)
{
if (sourceXml == null)
return null;
RoadMap roadMap = new RoadMap();
if (ValidateSchema(sourceXml))
{
XmlNode graph = sourceXml.SelectNodes("/graph").Item(0);
XmlNodeList nodes = graph.SelectNodes("node");
foreach (XmlNode node in nodes)
{
RoadNodeRole nodeRole = RoadNodeRole.Normal;
if (node.Attributes["role"] != null && node.Attributes["role"].Value == "start")
{
nodeRole = RoadNodeRole.Start;
}
else if (node.Attributes["role"] != null &&node.Attributes["role"].Value == "finish")
{
nodeRole = RoadNodeRole.Finish;
}
RoadNodeState nodeState = RoadNodeState.Ok;
if (node.Attributes["status"] != null && node.Attributes["status"].Value == "crash")
{
nodeState = RoadNodeState.Crash;
}
int nodeId = Convert.ToInt32(node.Attributes["id"].Value);
RoadNode roadNode = new RoadNode(nodeId, nodeRole, nodeState);
XmlNodeList links = node.SelectNodes("link");
foreach (XmlNode link in links)
{
int linkRef = Convert.ToInt32(link.Attributes["ref"].Value);
int linkWeight = Convert.ToInt32(link.Attributes["weight"].Value);
RoadLink roadLink = new RoadLink(linkWeight, linkRef);
roadNode.Links.Add(roadLink);
}
roadMap.Nodes.Add(roadNode);
}
}
return roadMap;
}
/// <summary>
/// Check if all links between nodes are correct.
/// </summary>
/// <param name="roadMap">road map to check</param>
/// <returns>String with errors descriptions or empty string if no errors found</returns>
private string CheckLinks(RoadMap roadMap)
{
string errors = string.Empty;
foreach (var node in roadMap.Nodes)
{
foreach (var link in node.Links)
{
try
{
//check if exactly one node exists by link ref
RoadNode neighbourByLink = roadMap.Nodes.Where(n => n.Id == link.RefNodeId).Single();
//check if exactly one back link exists and has the same weight as direct link
RoadLink backLink = neighbourByLink.Links.Where(l => l.RefNodeId == node.Id && l.Weight == link.Weight).Single();
}
catch (InvalidOperationException)
{
errors += string.Format("Node {0} has wrong link\n", node.Id);
}
}
}
return(errors);
}
/// <summary>
/// Get non-crashed nodes connected with the node
/// </summary>
/// <param name="node"></param>
/// <returns>list of neighbour nodes</returns>
private List<RoadNode> GetNeighbours(RoadNode node)
{
if (node == null)
return null;
List<RoadNode> neighbours = new List<RoadNode>();
foreach (var link in node.Links)
{
RoadNode neighbourByLink = roadMap.Nodes.Where(n => n.Id == link.RefNodeId).Single();
if (neighbourByLink.State == RoadNodeState.Ok)
{
neighbours.Add(neighbourByLink);
}
}
return neighbours;
}
/// <summary>
/// Recurcively find all paths from node to finishNode.
/// Deep graph search algorithm is used.
/// </summary>
/// <param name="node">node</param>
private void FindPaths(RoadNode node)
{
if (node == null)
return;
if (node == finishNode)
{
//if we have reached finish node, remember the current path
pathsFound.Add((RoadPath)currentPath.Clone());
}
else
{
List<RoadNode> neighbours = GetNeighbours(node);
foreach (RoadNode neighbour in neighbours)
{
if (!visitedNodes.Contains(neighbour))
{
visitedNodes.Add(neighbour);
currentPath.Push(neighbour);
FindPaths(neighbour);
visitedNodes.Remove(neighbour);
currentPath.Pop();
}
}
}
}
