Mai intai trebuie sa te autentifici.
Cod sursa(job #1708663)
Utilizator | Data | 27 mai 2016 19:13:03 | |
---|---|---|---|
Problema | Arbore partial de cost minim | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 1.92 kb |
#include <fstream>
#include <cstdio>
#include <algorithm>
using namespace std;
class InputReader {
public:
InputReader() {}
InputReader(const char *file_name) {
input_file = fopen(file_name, "r");
cursor = 0;
fread(buffer, SIZE, 1, input_file);
}
inline InputReader &operator >>(int &n) {
while((buffer[cursor] < '0' || buffer[cursor] > '9')&&buffer[cursor]!='-') {
advance();
}
n =0;
semn= 1;
if(buffer[cursor]=='-') semn=-1,advance();
while('0' <= buffer[cursor] && buffer[cursor] <= '9') {
n = n * 10 + buffer[cursor] - '0';
advance();
}
n*=semn;
return *this;
}
private:
FILE *input_file;
static const int SIZE = 1 << 17;
int cursor,semn;
char buffer[SIZE];
inline void advance() {
++ cursor;
if(cursor == SIZE) {
cursor = 0;
fread(buffer, SIZE, 1, input_file);
}
}
}f("apm.in");
struct el{int x,y,c;}v[1<<18];
int i,n,m,t,S,sol[1<<18],GR[1<<18];
struct cmp
{
bool operator () (el a,el b)
{
return a.c<b.c;
}
};
inline int gr(int i)
{
if(GR[i]==i) return i;
GR[i]=gr(GR[i]);
return GR[i];
}
inline void unite(int i,int j)
{
GR[gr(i)]=gr(j);
}
int main ()
{
f>>n>>m;
for(i=1;i<=m;++i)
f>>v[i].x>>v[i].y>>v[i].c;
sort(v+1,v+m+1,cmp());
for(i=1;i<=n;++i) GR[i]=i;
for(i=1;i<=m;++i)
if(gr(v[i].x)!=gr(v[i].y))
{
S+=v[i].c;
unite(v[i].x,v[i].y);
sol[++t]=i;
}
freopen("apm.out","w",stdout);
printf("%d\n%d\n",S,n-1);
for(i=1;i<n;++i)
printf("%d %d\n",v[sol[i]].x,v[sol[i]].y);
return 0;
}