public static Boolean IsBiPartite(Graph graph)
{
Boolean[] visited = new Boolean[graph.VerticesCount];
Boolean[] color = new Boolean[graph.VerticesCount];
Boolean isBiPartite = true;
for (int i = 0; i < graph.VerticesCount; i++)
{
if (!visited[i])
{
if (!IsBiPartite(i))
{
break;
}
}
}
return(isBiPartite);
Boolean IsBiPartite(Int32 vertice)
{
visited[vertice] = true;
using (var adjacents = graph.GetAdjacentVertices(vertice).GetEnumerator())
{
while (isBiPartite && adjacents.MoveNext())
{
// If one of my adjacents was visited and his color is equal to mine
// it means I'm pointing to a vertice that is on the same side as me.
//
// 0 ------> 2
// ^
// |
// |
// 0 ------> 1
if (!visited[adjacents.Current])
{
color[adjacents.Current] = !color[vertice];
IsBiPartite(adjacents.Current);
}
else if (color[adjacents.Current] == color[vertice])
{
isBiPartite = false;
}
}
}
return(isBiPartite);
}
}
private void DFS(Graph graph, Int32 vertice)
{
this._visited[vertice] = true;
this._ids[vertice] = this.Count;
foreach (Int32 adjacentVertice in graph.GetAdjacentVertices(vertice))
{
if (!this._visited[adjacentVertice])
{
this.DFS(graph, adjacentVertice);
}
}
}
public static Boolean HasCycle(Graph graph)
{
Boolean[] visited = new Boolean[graph.VerticesCount];
Boolean hasCycle = false;
for (int i = 0; i < graph.VerticesCount; i++)
{
if (!visited[i])
{
if (HasCycle(i, i))
{
break;
}
}
}
return(hasCycle);
Boolean HasCycle(Int32 vertice, Int32 parentVertice)
{
visited[vertice] = true;
using (var adjacents = graph.GetAdjacentVertices(vertice).GetEnumerator())
{
while (!hasCycle && adjacents.MoveNext())
{
if (adjacents.Current == vertice) // Self-loop: my adjacent is me.
{
hasCycle = true;
}
else if (!visited[adjacents.Current])
{
HasCycle(adjacents.Current, vertice);
}
else if (adjacents.Current != parentVertice) // Back-edge: if it's visited and not my parent so it looped to a vertice.
{
hasCycle = true;
}
}
}
return(hasCycle);
}
}