int _IsolateOuterplanarObstruction(graphP theGraph, int v, int R)
{
int RetVal;
/* A subgraph homeomorphic to K_{2,3} or K_4 will be isolated by using the visited
flags, set=keep edge/vertex and clear=omit. Here we initialize to omit all, then we
subsequently set visited on all edges and vertices in the homeomorph. */
_ClearVisitedFlags(theGraph);
/* Next we determineg which of the non-outerplanarity Minors was encountered
and the principal bicomp on which the isolator will focus attention. */
if (_ChooseTypeOfNonOuterplanarityMinor(theGraph, v, R) != OK)
return NOTOK;
/* Find the path connecting the pertinent vertex w with the current vertex v */
if (theGraph->IC.minorType & MINORTYPE_B)
{
isolatorContextP IC = &theGraph->IC;
int SubtreeRoot = gp_GetVertexLastPertinentRootChild(theGraph, IC->w);
if (_FindUnembeddedEdgeToSubtree(theGraph, IC->v, SubtreeRoot, &IC->dw) != TRUE)
return NOTOK;
}
else
{
isolatorContextP IC = &theGraph->IC;
if (_FindUnembeddedEdgeToCurVertex(theGraph, IC->w, &IC->dw) != TRUE)
return NOTOK;
}
/* For minor E, we need to find and mark an X-Y path */
if (theGraph->IC.minorType & MINORTYPE_E)
{
if (_MarkHighestXYPath(theGraph) != TRUE)
return NOTOK;
}
/* Call the appropriate isolator */
if (theGraph->IC.minorType & MINORTYPE_A)
RetVal = _IsolateOuterplanarityObstructionA(theGraph);
else if (theGraph->IC.minorType & MINORTYPE_B)
RetVal = _IsolateOuterplanarityObstructionB(theGraph);
else if (theGraph->IC.minorType & MINORTYPE_E)
RetVal = _IsolateOuterplanarityObstructionE(theGraph);
else
RetVal = NOTOK;
/* Delete the unmarked edges and vertices, and return */
if (RetVal == OK)
RetVal = _DeleteUnmarkedVerticesAndEdges(theGraph);
return RetVal;
}
int _IsolateMinorE2(graphP theGraph)
{
isolatorContextP IC = &theGraph->IC;
_ClearVisitedFlags(theGraph);
IC->v = IC->uz;
IC->dw = IC->dz;
IC->z = IC->uz = IC->dz = NIL;
theGraph->IC.minorType ^= MINORTYPE_E;
theGraph->IC.minorType |= (MINORTYPE_A|MINORTYPE_E2);
return _IsolateMinorA(theGraph);
}
int _IsolateMinorE2(graphP theGraph)
{
isolatorContextP IC = &theGraph->IC;
// Note: The x-y path was already marked, due to identifying E as the type of non-planarity minor,
// but we're reducing to Minor A, which does not include the x-y path, so the visited flags are
// cleared as a convenient, if somewhat wasteful, way to clear the marking on the x-y path
_ClearVisitedFlags(theGraph);
IC->v = IC->uz;
IC->dw = IC->dz;
IC->z = IC->uz = IC->dz = NIL;
theGraph->IC.minorType ^= MINORTYPE_E;
theGraph->IC.minorType |= (MINORTYPE_A|MINORTYPE_E2);
return _IsolateMinorA(theGraph);
}
int _IsolateKuratowskiSubgraph(graphP theGraph, int v, int R)
{
int RetVal;
/* A subgraph homeomorphic to K_{3,3} or K_5 will be isolated by using the visited
flags, set=keep edge/vertex and clear=omit. Here we initialize to omit all, then we
subsequently set visited on all edges and vertices in the homeomorph. */
_ClearVisitedFlags(theGraph);
/* Next, we determine which of the non-planarity Minors was encountered
and the principal bicomp on which the isolator will focus attention. */
if (_ChooseTypeOfNonplanarityMinor(theGraph, v, R) != OK)
return NOTOK;
if (_InitializeIsolatorContext(theGraph) != OK)
return NOTOK;
/* Call the appropriate isolator */
if (theGraph->IC.minorType & MINORTYPE_A)
RetVal = _IsolateMinorA(theGraph);
else if (theGraph->IC.minorType & MINORTYPE_B)
RetVal = _IsolateMinorB(theGraph);
else if (theGraph->IC.minorType & MINORTYPE_C)
RetVal = _IsolateMinorC(theGraph);
else if (theGraph->IC.minorType & MINORTYPE_D)
RetVal = _IsolateMinorD(theGraph);
else if (theGraph->IC.minorType & MINORTYPE_E)
RetVal = _IsolateMinorE(theGraph);
else
RetVal = NOTOK;
/* Delete the unmarked edges and vertices, and return */
if (RetVal == OK)
RetVal = _DeleteUnmarkedVerticesAndEdges(theGraph);
return RetVal;
}
