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#include <fstream>
#include <vector>
using namespace std;
const int N = 2e5;
const int INF = 1015;
struct muchie
{
int varf, cost;
};
int nh, n, d[N+1], h[N], poz[N+1], pred[N+1];
bool in_apm[N+1];
vector <muchie> a[N+1];
int tata(int p)
{
return ((p - 1) / 2);
}
int fiu_s(int p)
{
return (2 * p + 1);
}
int fiu_d(int p)
{
return (2 * p + 2);
}
void schimba(int p1, int p2)
{
swap(h[p1], h[p2]);
poz[h[p1]] = p1;
poz[h[p2]] = p2;
}
void urca(int p)
{
while (p > 0 && d[h[p]] < d[h[tata(p)]])
{
schimba(p, tata(p));
p = tata(p);
}
}
void adauga(int pv)
{
h[nh++] = pv;
poz[pv] = nh - 1;
urca(nh - 1);
}
void coboara(int p)
{
int fs = fiu_s(p), fd = fiu_d(p), optim = p;
if (fs < nh && d[h[fs]] < d[h[optim]])
{
optim = fs;
}
if (fd < nh && d[h[fd]] < d[h[optim]])
{
optim = fd;
}
if (optim != p)
{
schimba(p, optim);
coboara(optim);
}
}
void sterge(int ph)
{
if (ph == nh - 1)
{
nh--;
return;
}
schimba(ph, nh - 1);
nh--;
urca(ph);
coboara(ph);
}
int prim()
{
///initializam d
d[1] = 0;
pred[1] = 0;
adauga(1);
in_apm[1] = false;
for (int i = 2; i <= n; i++)
{
d[i] = INF;
pred[i] = 0;
adauga(i);
in_apm[i] = false;
}
int cost_total = 0;
while (nh > 0)
{
int x = h[0];
sterge(poz[x]);
in_apm[x] = true;
cost_total += d[x];
for (auto e: a[x])
{
int y = e.varf;
int c = e.cost;
if (!in_apm[y] && c < d[y])
{
d[y] = c;
pred[y] = x;
urca(poz[y]);
}
}
}
return cost_total;
}
int main()
{
ifstream in("apm.in");
ofstream out("apm.out");
int m;
in >> n >> m;
for (int i = 0; i < m; i++)
{
int x, y, c;
in >> x >> y >> c;
a[x].push_back((muchie){y, c});
a[y].push_back((muchie){x, c});
}
out << prim() << "\n" << n - 1 << "\n";
for (int i = 2; i <= n; i++)
{
out << i << " " << pred[i] << "\n";
}
in.close();
out.close();
return 0;
}