public static void make_connected(
/* Add edges to make graph connected. */
vtx_data **graph, /* graph data structure */
int nvtxs, /* number of vertices in graph */
int *nedges, /* number of edges in graph */
int *mark, /* space for nvtxs+1 ints */
int *vtxlist, /* space for nvtxs ints */
connect_data **cdata, /* space for connectivity data */
bool useEdgeWeights /* are edges of graph weighted? */
)
{
edgeslist *new_edges; /* list of edges connecting graph */
edgeslist *prev_edge; /* pointer for manipulating edge list */
edgeslist *curr_edge; /* pointer for manipulating edge list */
edgeslist *next_edge; /* pointer for manipulating edge list */
int nadded; /* number of edges being added */
/* First find edges needed to make graph connected. */
nadded = find_edges(graph, nvtxs, mark, vtxlist, &new_edges);
/* Now add these needed edges to graph data structure if needed. */
if (nadded == 0)
{
*cdata = null;
}
else
{
*cdata = (connect_data *)Marshal.AllocHGlobal(sizeof(connect_data));
(*cdata)->old_edges = null;
(*cdata)->old_ewgts = null;
add_edges(graph, new_edges, &(*cdata)->old_edges, &(*cdata)->old_ewgts, useEdgeWeights);
*nedges += nadded;
/* Now, reverse the order of the new_edges list for consistency with */
/* the removal order. */
curr_edge = new_edges->next;
new_edges->next = null;
prev_edge = new_edges;
while (curr_edge != null)
{
next_edge = curr_edge->next;
curr_edge->next = prev_edge;
prev_edge = curr_edge;
curr_edge = next_edge;
}
(*cdata)->new_edges = prev_edge;
}
}
public static void make_unconnected(
/* Restore graph to its pristine state and free space for connectivity. */
vtx_data **graph, /* graph data structure */
int *nedges, /* number of edges in graph */
connect_data **cdata, /* space for connectivity data */
bool useEdgeWeights /* are edges of graph weighted? */
)
{
ilists * old_edges = null; /* edges overwritten for connecting */
flists * old_ewgts = null; /* weights of edges overwritten */
edgeslist *new_edges; /* list of edges connecting graph */
ilists * tempi; /* used for freeing space */
flists * tempf; /* used for freeing space */
edgeslist *tempe; /* used for freeing edgelist space */
edgeslist *edges; /* loops through new edges */
int vtx; /* vertex in an added edge */
int j; /* loop counters */
if (*cdata == null)
{
return;
}
old_edges = (*cdata)->old_edges;
old_ewgts = (*cdata)->old_ewgts;
new_edges = (*cdata)->new_edges;
Marshal.FreeHGlobal((IntPtr)(*cdata));
*cdata = null;
edges = new_edges;
while (edges != null)
{
/* Restore edges and weights to original status. */
(*nedges)--;
for (j = 0; j < 2; j++)
{
if (j == 0)
{
vtx = edges->vtx2;
}
else
{
vtx = edges->vtx1;
}
Marshal.FreeHGlobal((IntPtr)(graph[vtx]->edges));
graph[vtx]->edges = old_edges->list;
graph[vtx]->nedges--;
tempi = old_edges;
old_edges = old_edges->next;
Marshal.FreeHGlobal((IntPtr)(tempi));
if (useEdgeWeights)
{
Marshal.FreeHGlobal((IntPtr)(graph[vtx]->ewgts));
graph[vtx]->ewgts = old_ewgts->list;
tempf = old_ewgts;
old_ewgts = old_ewgts->next;
Marshal.FreeHGlobal((IntPtr)(tempf));
}
}
tempe = edges;
edges = edges->next;
Marshal.FreeHGlobal((IntPtr)(tempe));
}
}
