static void BeGreedy(this IGraph_long graph, long[] colorGraph, ref long liveVertexBits, int c)
{
while (true)
{
var originalBits = liveVertexBits;
var bits = liveVertexBits;
while (bits != 0)
{
var bit = bits & -bits;
bits ^= bit;
var colorCount = 0;
for (int i = c; i < colorGraph.Length; i++)
{
if ((bit & colorGraph[i]) != 0)
{
colorCount++;
}
}
if (colorCount > graph.DegreeInSet(bit.Extract(), liveVertexBits))
{
liveVertexBits ^= bit;
}
}
if (liveVertexBits == originalBits)
{
break;
}
}
}
static bool IsChoosable(this IGraph_long graph, long[] colorGraph, long liveVertexBits, int c)
{
graph.BeGreedy(colorGraph, ref liveVertexBits, c);
if (liveVertexBits == 0)
{
return(true);
}
if ((liveVertexBits & ~colorGraph.Or(c)) != 0)
{
return(false);
}
var choosable = false;
var V = colorGraph[c] & liveVertexBits;
foreach (var C in graph.MaximalIndependentSubsets(V))
{
if (graph.IsChoosable(colorGraph, liveVertexBits ^ C, c + 1))
{
choosable = true;
break;
}
}
return(choosable);
}
public static bool IsChoosable(this IGraph_long graph, long[] colorGraph)
{
return(graph.IsChoosable(colorGraph, Enumerable.Range(0, graph.N).To_long(), 0));
}
public static bool IsChoosable(this IGraph_long graph, long[] colorGraph, long subset)
{
return(graph.IsChoosable(colorGraph, subset, 0));
}
public static bool IsFChoosable(this IGraph_long graph, Func <int, int> f, out List <List <int> > badAssignment)
{
badAssignment = null;
var liveVertexBits = Enumerable.Range(0, graph.N).To_long();
var sizes = graph.Vertices.Select(v => f(v)).ToList();
var maxListSize = sizes.Max();
for (int potSize = maxListSize; potSize < graph.N; potSize++)
{
foreach (var colorGraph in BitLevelGeneration.Assignments_long.Enumerate(sizes, potSize))
{
if (potSize > maxListSize)
{
var xx = 0L;
for (int i = 0; i < colorGraph.Length; i++)
{
xx |= colorGraph[i];
if (xx.PopulationCount() <= i + 1)
{
goto skip;
}
}
for (int i = 0; i < colorGraph.Length; i++)
{
for (int j = i + 1; j < colorGraph.Length; j++)
{
if ((colorGraph[i] & colorGraph[j]) == 0)
{
goto skip;
}
}
}
foreach (var color in colorGraph)
{
if (graph.IsIndependent(color))
{
goto skip;
}
}
}
if (!graph.IsChoosable(colorGraph, liveVertexBits, 0))
{
badAssignment = new List <List <int> >();
foreach (var v in graph.Vertices)
{
var list = new List <int>();
var bit = 1L << v;
for (int i = 0; i < colorGraph.Length; i++)
{
if ((bit & colorGraph[i]) != 0)
{
list.Add(i);
}
}
badAssignment.Add(list);
}
return(false);
}
skip :;
}
}
return(true);
}
