Cod sursa(job #1335996)

Utilizator nicol.bolasNicol Bolas nicol.bolas Data 6 februarie 2015 12:13:12
Problema Algoritmul lui Dijkstra Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.89 kb
#include<fstream>
#include<vector>
#include<cstring>
using namespace std;
#define NMAX 50005
#define INF 0x3f3f3f3f
ifstream fin("dijkstra.in");
ofstream fout("dijkstra.out");
vector < pair <int,int> > v[NMAX];
int n,m,x,y,c,dh,H[NMAX],D[NMAX],P[NMAX];
inline void adaugare(int nr)
{
    int aux,nod,tata;
    H[++dh]=nr, P[nr]=dh;
    nod=dh, tata=nod>>1;
    while (tata)
    {
        if (D[H[nod]]>=D[H[tata]])
            break;
        aux=H[nod], H[nod]=H[tata], H[tata]=aux;
        P[H[nod]]=nod, P[H[tata]]=tata;
        nod=tata, tata=nod>>1;
    }
}
inline void extrage()
{
    int aux,nod,fiu;
    H[1]=H[dh--], P[H[1]]=1, P[H[dh+1]]=0;
    nod=1, fiu=2;
    while (fiu<=dh)
    {
        if (fiu<dh && D[H[fiu+1]]<D[H[fiu]])
            ++fiu;
        if (D[H[fiu]]>=D[H[nod]])
            break;
        aux=H[fiu], H[fiu]=H[nod], H[nod]=aux;
        P[H[fiu]]=fiu, P[H[nod]]=nod;
        nod=fiu, fiu=nod<<1;
    }
}
inline void actualizare(int nr)
{
    int aux,nod,tata;
    nod=nr, tata=nod>>1;
    while (tata)
    {
        if (D[H[nod]]>=D[H[tata]])
            break;
        aux=H[nod], H[nod]=H[tata], H[tata]=aux;
        P[H[nod]]=nod, P[H[tata]]=tata;
        nod=tata, tata=nod>>1;
    }
}
int main()
{
    int i;
    fin>>n>>m;
    for (i=1;i<=m;++i)
    {
        fin>>x>>y>>c;
        v[x].push_back(make_pair(y,c));
    }
    memset(D,0x3f,sizeof(D));
    D[1]=0, H[dh=1]=1;
    while (dh)
    {
        x=H[1]; extrage();
        for (i=0;i<v[x].size();++i)
        {
            y=v[x][i].first, c=v[x][i].second;
            if (D[y]>D[x]+c)
            {
                D[y]=D[x]+c;
                if (P[y]) actualizare(P[y]);
                else adaugare(y);
            }
        }
    }
    for (i=2;i<=n;++i)
        if (D[i]==INF) fout<<"0 ";
        else fout<<D[i]<<" ";
    fout<<"\n";
    return 0;
}