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Cod sursa(job #990885)
#include <cstdio>
#include <vector>
#include <algorithm>
#define INF 2000000000
#define NMAX 50001
using namespace std;
int n, x0;
vector <vector < pair<int,int> > > G(NMAX);
vector<int> dmin(NMAX, INF); //distantele minime
//vector<int> prec (NMAX); //pot reconstitui drumul
vector<bool> M(NMAX, false); //multimea varfurilor selectate
//vector<int> poz(NMAX, -1); //poz[i]=-1 daca vf i nu a fost pus in heap, respectiv pozitia nodului i in heap
vector<int> H;
class ComparVf
{public:
bool operator () (const int& x, const int& y)
{ return dmin[x]>dmin[y]; }
};
void citire();
void dijkstra();
void afisare();
int main()
{
citire();
dijkstra();
afisare();
return 0;
}
void citire()
{int i, m, x, y, c;
FILE * fin=fopen("dijkstra.in","r");
fscanf(fin,"%d %d", &n, &m); x0=1;
for (i=0; i<m; i++)
{ fscanf(fin,"%d %d %d", &x, &y, &c);
G[x].push_back(make_pair(y,c)); }
}
void dijkstra()
{int i, nrs=0, j, vfmin;
vector<int>::iterator it;
//for (i=1; i<=n; i++) prec[i]=x0;
dmin[x0]=0; //prec[x0]=-1;
H.push_back(x0); push_heap(H.begin(), H.end(), ComparVf());
while (nrs<n) //nu au fost selectate toate varfurile
{if (H.empty()) break;
vfmin=H.front();
pop_heap(H.begin(), H.end(), ComparVf());
H.pop_back();
M[vfmin]=true; nrs++;
for (j=0; j<G[vfmin].size(); j++)
if (!M[G[vfmin][j].first]) //nu a fost deja selectat
if (dmin[G[vfmin][j].first]>dmin[vfmin]+G[vfmin][j].second) //obtin ceva mai bun
{
dmin[G[vfmin][j].first]=dmin[vfmin]+G[vfmin][j].second;
//prec[G[vfmin][j].first]=vfmin;
it=find(H.begin(), H.end(), G[vfmin][j].first);
if (it==H.end())//nu e in heap
{H.push_back(G[vfmin][j].first);
push_heap(H.begin(), H.end(), ComparVf());}
else //restaurez
{push_heap(H.begin(), it, ComparVf());}
}
}
}
void afisare()
{
FILE * fout=fopen("dijkstra.out","w");
int i;
for (i=1; i<=n; i++)
if (i!=x0)
if (dmin[i]!=INF) fprintf(fout,"%d ",dmin[i]);
else
fprintf(fout,"0 ");
fclose(fout);
}