Cod sursa(job #1359542)

Utilizator mihaivasilacheMIhai Vasilache mihaivasilache Data 24 februarie 2015 23:22:30
Problema Algoritmul lui Dijkstra Scor 0
Compilator cpp Status done
Runda Arhiva educationala Marime 2.69 kb
#include <fstream>
using namespace std;
ofstream fout("dijkstra.out");
int dist[1001],poz[1001],h[1001],n,m,x;
struct liste
{
    int nod,distanta;
} l[1001][1001];
int tata(int i)
{
    return i/2;
}
int fiust (int i)
{
    return i*2;
}
int fiudr (int i)
{
    return i*2+1;
}
void swapp(int a, int b)
{
    int aux;
    aux=h[a];
    h[a]=h[b];
    h[b]=aux;
}
void precolate(int nod,int n)
{
    while(nod*2<=n&&(dist[h[nod]]>dist[h[fiust(nod)]]||dist[h[nod]]>dist[h[fiudr(nod)]]))
    {
        if(dist[h[fiust(nod)]]>dist[h[fiudr(nod)]])
        {
            poz[h[nod]]=fiudr(nod);
            poz[h[fiudr(nod)]]=nod;
            swapp(nod,fiudr(nod));
            nod=fiudr(nod);
        }
        else
        {
            poz[h[nod]]=fiust(nod);
            poz[h[fiust(nod)]]=nod;
            swapp(nod,fiust(nod));
            nod=fiust(nod);
        }
    }
}
void sift(int nod,int n)
{
    while(nod>=1&&dist[h[nod]]<dist[h[tata(nod)]])
    {
        poz[h[nod]]=tata(nod);
        poz[tata(nod)]=nod;
        swapp(nod,tata(nod));
        nod=tata(nod);
    }
}
void afisare()
{
    int i;
    for(i=1; i<=n; i++)
        if(i!=x)
           {
                if(dist[i]!=1001)
                    fout<<dist[i]<<" ";
                else fout<<0<<" ";
           }
    fout<<'\n';
}
void dijkstraheap()
{
    int k,i;
    k=1;
    for(i=1; i<=n; i++)
    {
        dist[i]=1001;
        poz[i]=-1;
    }
    h[k]=x;
    poz[x]=1;
    dist[x]=0;
    while(k)
    {
        int minim;
        minim=h[1];
        swapp(1,k);
        poz[h[1]]=1;
        k=k-1;
        precolate(1,k);
        for(i=1; i<=l[minim][0].nod; ++i)
        {
                if(dist[l[minim][i].nod]>dist[minim]+l[minim][i].distanta)
                {
                    if(poz[l[minim][i].nod]==-1)
                    {
                        dist[l[minim][i].nod]=dist[minim]+l[minim][i].distanta;
                        ++k;
                        h[k]=l[minim][i].nod;
                        poz[h[k]]=k;
                        sift(k,k);
                    }
                    else
                    {
                        dist[l[minim][i].nod]=dist[minim]+l[minim][i].distanta;
                        sift(poz[l[minim][i].nod],k);
                    }
            }
        }
    }
}
int main()
{
    int y,z,c,i;
    FILE*fin;
    fin=fopen("dijkstra.in","r");
    fscanf(fin,"%d%d%d",&n,&m,&x);
    for(i=1; i<=m; i++)
    {
        fscanf(fin,"%d%d%d",&y,&z,&c);
        l[y][++l[y][0].nod].nod=z;
        l[y][l[y][0].nod].distanta=c;
    }
    dijkstraheap();
    afisare();
    fout<<endl;
    return 0;
}