``````#include <stdio.h>
#include <stdlib.h>
#include <ogdf/basic/Graph.h>
#include <ogdf/graphalg/Triconnectivity.h>
#include <chrono>

using namespace ogdf;

int main(int n_args, char** args)
{
if (n_args!= 3)
{
printf("\n usage: %s <input file> <output file>\n\n", args[0]);
exit(-1);
}

/* read graph from file */
FILE* fp = fopen(args[1],"r");
int n,m;
fscanf(fp,"%d %d",&n,&m);
Graph G;
node* vertex = new node[n];
for(int i=0;i<n;i++){vertex[i]=G.newNode();} //create vertices
for(int i=0;i<m;i++)
{
int x,y;
fscanf(fp,"%d %d",&x,&y);
G.newEdge(vertex[x-1],vertex[y-1]); //create edges
}
fclose(fp);

using namespace std::chrono;
high_resolution_clock::time_point t1 = high_resolution_clock::now();

/* initialize all count(v) to 0 */
int* count = new int[n];
for(int i=0;i<n;i++){count[i]=0;}

/* get the triconnected components */
Triconnectivity tricComp(G);

/* prepare a stack to keep track of the vertices of the polygons (since the polygons appear as sets of edges) */
char* found = new char[n];
for(int i=0;i<n;i++){found[i]=0;}
int* vertexStack = new int[n];

/* process only the polygons; a vertex forms vertex-edge cuts with all the real edges it is not incident to */
for(int i=0; i<tricComp.m_numComp; i++)
{
if(tricComp.m_component[i].m_type==Triconnectivity::CompType::polygon)
{
int n_realEdges=0;
int SP=0;
for(edge e : tricComp.m_component[i].m_edges)
{
int x=e->source()->index();
int y=e->target()->index();
if(!found[x]){found[x]=1;vertexStack[SP++]=x;}
if(!found[y]){found[y]=1;vertexStack[SP++]=y;}
if(tricComp.m_pGC->original(e))
{
n_realEdges++;
count[e->source()->index()]--; count[e->target()->index()]--;
}
}
for(int t=0;t<SP;t++)
{
int v=vertexStack[t];
count[v]+=n_realEdges;
found[v]=0;
}
}
}

high_resolution_clock::time_point t2 = high_resolution_clock::now();
duration<double> time_span = duration_cast<duration<double>>(t2 - t1);

fp = fopen(args[2],"w");
for(int i=0;i<n;i++){fprintf(fp,"%d\n",count[i]);}
fprintf(fp,"%lf\n",(double)time_span.count());
fclose(fp);

printf("%f\n",time_span.count());
return 0;
}

``````