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Cod sursa(job #595464)
#include<cstdio>
#include<algorithm>
using namespace std;
int n,m;
struct Muchie{int x,y,cost;};
Muchie G[400010];
int arbore[200010],c[200010];
inline bool Ordonare(const Muchie A,const Muchie B)
{
if(A.cost==B.cost)
{
if(A.x==B.x)
return A.y<B.y;
return A.x<B.x;
}
return A.cost<B.cost;
}
void Initializari()
{
int i;
freopen("apm.in","r",stdin);
scanf("%d %d",&n,&m);
for(i=1;i<=m;i++)
scanf("%d %d %d",&G[i].x,&G[i].y,&G[i].cost);
for(i=1;i<=n;i++)
c[i]=i;
}
void Kruskal()
{
int i,j,minim,maxim,nr=0; //nr = numarul de muchii selectate
for(i=1;nr<n-1;i++)
{
if(c[G[i].x]!=c[G[i].y]) //daca muchia nu ar forma cicluri cu cele deja selectate
{
arbore[++nr]=i; //selectez muchia i
//unific cele doua componente conexe
if(c[G[i].x]<c[G[i].y])
{
minim=c[G[i].x];
maxim=c[G[i].y];
}
else
{
minim=c[G[i].y];
maxim=c[G[i].x];
}
for(j=1;j<=n;j++)
if(c[j]==maxim)
c[j]=minim;
}
}
}
void AfisareArbore()
{
freopen("apm.out","w",stdout);
int i,cost=0;
for(i=1;i<n;i++)
{
cost+=G[arbore[i]].cost;
}
printf("%d\n",cost);
printf("%d\n",n-1);
for(i=1;i<n;i++)
{
printf("%d %d\n",G[arbore[i]].x,G[arbore[i]].y);
}
}
int main()
{
Initializari();
sort(G+1,G+m+1,Ordonare); //sortez muchiile crescator dupa cost
Kruskal(); //determin arborele partial de cost minim
//selectand n-1 muchii de cost minim,care nu formeaza cicluri
AfisareArbore(); //afisez APM
return 0;
}