public void Compute()
{
this.joins.Clear();
this.startVertex = null;
UndirectedDepthFirstSearchAlgorithm udfs =
new UndirectedDepthFirstSearchAlgorithm(this.VisitedGraph);
udfs.TreeEdge+=new EdgeEventHandler(udfs_TreeEdge);
udfs.StartVertex+=new VertexEventHandler(udfs_StartVertex);
udfs.Compute();
}
public void Init()
{
parents = new VertexVertexDictionary();
discoverTimes = new VertexIntDictionary();
finishTimes = new VertexIntDictionary();
time = 0;
g = new BidirectionalGraph(true);
dfs = new UndirectedDepthFirstSearchAlgorithm(g);
dfs.StartVertex += new VertexEventHandler(this.StartVertex);
dfs.DiscoverVertex += new VertexEventHandler(this.DiscoverVertex);
dfs.ExamineEdge += new EdgeEventHandler(this.ExamineEdge);
dfs.TreeEdge += new EdgeEventHandler(this.TreeEdge);
dfs.BackEdge += new EdgeEventHandler(this.BackEdge);
dfs.FinishVertex += new VertexEventHandler(this.FinishVertex);
}
private void UndirectedDepthFirstSearch <TVertex, TEdge>(IUndirectedGraph <TVertex, TEdge> g)
where TEdge : IEdge <TVertex>
{
var parents = new Dictionary <TVertex, TVertex>();
var discoverTimes = new Dictionary <TVertex, int>();
var finishTimes = new Dictionary <TVertex, int>();
int time = 0;
var dfs = new UndirectedDepthFirstSearchAlgorithm <TVertex, TEdge>(g);
dfs.StartVertex += args =>
{
Assert.Equal(GraphColor.White, dfs.VertexColors[args]);
Assert.False(parents.ContainsKey(args));
parents[args] = args;
};
dfs.DiscoverVertex += args =>
{
Assert.Equal(GraphColor.Gray, dfs.VertexColors[args]);
Assert.Equal(GraphColor.Gray, dfs.VertexColors[parents[args]]);
discoverTimes[args] = time++;
};
dfs.ExamineEdge += (sender, args) =>
{
Assert.Equal(GraphColor.Gray, dfs.VertexColors[args.Source]);
};
dfs.TreeEdge += (sender, args) =>
{
var source = args.Source;
var target = args.Target;
Assert.Equal(GraphColor.White, dfs.VertexColors[target]);
parents[target] = source;
};
dfs.BackEdge += (sender, args) =>
{
Assert.Equal(GraphColor.Gray, dfs.VertexColors[args.Target]);
};
dfs.ForwardOrCrossEdge += (sender, args) =>
{
Assert.Equal(GraphColor.Black, dfs.VertexColors[args.Target]);
};
dfs.FinishVertex += args =>
{
Assert.Equal(GraphColor.Black, dfs.VertexColors[args]);
finishTimes[args] = time++;
};
dfs.Compute();
// check
// all vertices should be black
foreach (var v in g.Vertices)
{
Assert.True(dfs.VertexColors.ContainsKey(v));
Assert.Equal(GraphColor.Black, dfs.VertexColors[v]);
}
foreach (var u in g.Vertices)
{
foreach (var v in g.Vertices)
{
if (!u.Equals(v))
{
Assert.True(
finishTimes[u] < discoverTimes[v] ||
finishTimes[v] < discoverTimes[u] ||
(
discoverTimes[v] < discoverTimes[u] &&
finishTimes[u] < finishTimes[v] &&
IsDescendant(parents, u, v)
) ||
(
discoverTimes[u] < discoverTimes[v] &&
finishTimes[v] < finishTimes[u] &&
IsDescendant(parents, v, u)
)
);
}
}
}
}
