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#include "graph.h"
#include <sstream>
#include "matrix.h"
int Graph::diameter(int *timesAttained)const
{
IntegerMatrix A(n,n);
for(int i=0;i<n;i++)
for(int j=0;j<n;j++)
A[i][j]=n;
for(set<Edge>::const_iterator i=edges.begin();i!=edges.end();i++)
{
A[i->a][i->b]=1;
if(!isDirected)A[i->b][i->a]=1;
}
for(int i=0;i<n;i++)A[i][i]=0;
bool wasChange=true;
while(wasChange)
{
wasChange=false;
for(int i=0;i<n;i++)
for(int j=0;j<n;j++)
{
int best=A[i][j];
for(int k=0;k<n;k++)
{
int s=A[i][k]+A[k][j];
if(s<best)
{
best=s;
wasChange=true;
}
}
A[i][j]=best;
}
}
int timesAttained2=0;
int ret=0;
for(int i=0;i<n;i++)
for(int j=0;j<n;j++)
{
if(A[i][j]>ret)
{
ret=A[i][j];
timesAttained2=0;
}
if(A[i][j]==ret)
timesAttained2++;
}
if(timesAttained)*timesAttained=timesAttained2;
return ret;
}
string Graph::toString()const
{
stringstream ret;
ret<<"("<<n<<",{"<<endl;
for(set<Edge>::const_iterator i=edges.begin();i!=edges.end();i++)
{
if(i!=edges.begin())ret<<","<<endl;
ret<<"("<<i->a<<","<<i->b<<")"<<endl;
}
ret<<"}"<<endl;
return ret.str();
}
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