//algorithm from course textbook
int kruskal(Matrix*result,DisjSets*dset,edge*ex,int len)
{
int edgeOK=0,i=0,sum=0;
edge * e =0;
int v1,v2;
qsort(ex,len,sizeof(edge), compare);// sorts edge by weights.
i=0;
while(edgeOK<(result->size)-1)
{
e=&ex[i++]; //selects minimum weighted edge.
v1=e->ea[0]; v2=e->ea[1];
int v1_eq = disj_find(dset,v1);
int v2_eq = disj_find(dset,v2);
if(v1_eq!=v2_eq)//checks their sets
{
edgeOK++;//accepted tree
result->data[v1][v2]=1;//print in result matrix
result->data[v2][v1]=1;
sum+=e->ea[2]; //adds weights to total
disj_union(dset,v1_eq,v2_eq);//now they are in same set
}
}
return sum;
}
/* Retorna um inteiro cujo valor maximo eh points->size-1 */
int find_edges_shorter_than(float dist, plist *points)
{
int edges;
int r1,r2;
lnk n,m; /* Cursores da lista de pontos */
float weigth;
dsets *dset;
dset = malloc(sizeof *dset);
init_dsets(dset,points->size);
edges=0;
for(n=points->head; n!=NULL; n=n->next)
for(m=points->head; m!=NULL; m=m->next)
{
if(n == m) continue;
weigth=distance(n->p,m->p);
if(weigth<dist)
{
/*printf("x(%d-%d) weigth = %f dist = %f\n",n->index,m->index,weigth,dist);*/
r1=disj_find(dset,n->index);
r2=disj_find(dset,m->index);
if(r1!=r2)
{
/*printf("UNION r1=%d r2=%d weigth=%f\n",r1,r2,weigth);
printPoint(n->p);
printPoint(m->p);*/
disj_union(dset,r1,r2);
edges++;
break;
}
}
}
free(dset);
return edges;
}
