Pagini recente » Cod sursa (job #406451) | Cod sursa (job #3164746) | Cod sursa (job #1208815) | Cod sursa (job #2619532) | Cod sursa (job #2758465)
#include <bits/stdc++.h>
using namespace std;
ifstream in("apm.in");
ofstream out("apm.out");
const int N = 200001 , INF = 1e9;
vector <pair <int, int>> a[N];
priority_queue <pair <int, int>> pq;
int d[N], pred[N] , n , m , cost;
bitset <N> selectat;
void prim_apm()
{
for(int i = 2; i <= n; i++)
{
d[i] = INF;
}
pq.push({0, 1});
while(!pq.empty())
{
int x = pq.top().second;
pq.pop();
if(selectat[x]) continue;
cost += d[x];
selectat[x] = true;
for(auto p : a[x])
{
int y = p.first, c = p.second;
if( !selectat[y] && c < d[y] )
{
d[y] = c, pred[y] = x;
pq.push({-c, y});
}
}
}
}
int main()
{
in >> n >> m;
for( int i = 0 ; i < m ; i++)
{
int x , y , c;
in >> x >> y >> c;
a[x].push_back({y, c});
a[y].push_back({x, c});
}
prim_apm();
out << cost << "\n" << n - 1 << "\n";
for(int i = 2; i <= n; i++)
{
out << i << " " << pred[i] << "\n";
}
return 0;
}