Pagini recente » Cod sursa (job #3350175) | Cod sursa (job #1312601) | Cod sursa (job #725618) | Cod sursa (job #460462) | Cod sursa (job #3342946)
#include <fstream>
#include <queue>
#define MMAX 400002
#define NMAX 200002
using namespace std;
ifstream fin("apm.in");
ofstream fout("apm.out");
struct muchie{
int x, y, c;
friend bool operator < (muchie a, muchie b);
};
int n,m;
int tata[NMAX];
int h[NMAX]; //h[x]=intaltimea arborelui cu inaltimea x
muchie apm[NMAX];
int costmin;
priority_queue<muchie> H;
bool operator < (muchie a, muchie b){
return a.c > b.c;
}
int Find(int x);
void Union(int x, int y);
void citire();
void kruskal();
void afisare();
int main()
{
citire();
kruskal();
afisare();
return 0;
}
void citire(){
int i,x,y,c;
muchie aux;
fin>>n>>m;
for(i=0;i<m;i++)
{
fin>>aux.x>>aux.y>>aux.c;
H.push(aux);
}
}
void kruskal(){
int rx,ry,nrsel;
muchie aux;
nrsel=0;
while(nrsel<n-1)
{
aux=H.top(); H.pop();
rx=Find(aux.x); ry=Find(aux.y);
if(rx!=ry)
{
costmin+=aux.c;
apm[++nrsel]=aux;
Union(rx,ry);
}
}
}
int Find(int x){
int y,rx;
//determin radacina arborelui
rx=x;
while(tata[rx])
rx=tata[rx];
//rx este radacina arborelui
//compresez drumul de la x la rx;
//fiecare nod de pe acest drum devine fiu al lui rx
while(tata[x] && tata[x]!=rx)
{
y=tata[x];
tata[x]=rx;
x=y;
}
return rx;
}
void Union(int x, int y){
int rx,ry;
//reuneste arborele in care se afla x cu arborele in care se afla y
rx=Find(x); ry=Find(y);
if(h[rx]<h[ry]) //rx devine fiul lui ry
tata[rx]=ry;
else
if(h[ry]<h[rx]) //ry devine fiul lui rx
tata[ry]=rx;
else //egalitate
{
tata[ry]=rx;
h[rx]++;
}
}
void afisare(){
int i;
fout<<costmin<<'\n'<<n-1<<'\n';
for(i=1;i<n;i++)
fout<<apm[i].x<<' '<<apm[i].y<<'\n';
}