Cod sursa(job #2269656)

Utilizator AndreiD31Dragan Andrei AndreiD31 Data 26 octombrie 2018 12:41:40
Problema Algoritmul lui Dijkstra Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 2.11 kb
#include <fstream>
#include <vector>
#include <climits>
using namespace std;
ifstream f("dijkstra.in");
ofstream g("dijkstra.out");


vector <int> a[50100];
vector <int> d[50100];


struct dist
{
    int poz,val;
}D[50100];

int n,fv[50100],w[50100],viz[50100];

void up(int p)
{
    if(p>1&&D[p].val<D[p/2].val)
    {

        swap(D[p],D[p/2]);
        fv[D[p].poz]=p;
        fv[D[p/2].poz]=p/2;

        up(p/2);
    }
}


void down(int p)
{
    if(2*p+1<=n&&(D[p].val>D[2*p].val||D[p].val>D[2*p+1].val))
    {
        if(D[2*p].val<D[2*p+1].val)
        {

            swap(D[2*p],D[p]);
            fv[D[p].poz]=p;
            fv[D[2*p].poz]=2*p;
            down(2*p);
        }
        else
        {

            swap(D[2*p+1],D[p]);
            fv[D[p].poz]=p;
            fv[D[2*p+1].poz]=2*p+1;
            down(2*p+1);
        }
    }
    else if(2*p<=n&&D[p].val>D[2*p].val)
    {
        swap(D[p],D[2*p]);
        fv[D[p].poz]=p;
        fv[D[2*p].poz]=2*p;
    }
}

void dijkstra(int s)
{
    int i,k,mini,x;
    for(i=1;i<=n;i++)
    {
        D[i].val=INT_MAX/2;
        D[i].poz=i;
    }

    w[s]=0;
    D[s].val=0;
    up(s);


    for(k=1;k<=n;k++)
    {
        mini=D[1].val;
        x=D[1].poz;

        if(mini!=INT_MAX/2)
        {
            D[1].val=INT_MAX/2;
            down(1);

            for(i=0;i<a[x].size();i++)
            {
                if(w[a[x][i]]>mini+d[x][i])
                {
                    w[a[x][i]]=mini+d[x][i];
                    D[fv[a[x][i]]].val=mini+d[x][i];
                    up(fv[a[x][i]]);
                }
            }

        }
    }


}


int m,i,x,j,cost,y;

int main()
{
    f>>n>>m;
    for(i=1;i<=n;i++)
    {
        D[i].val=INT_MAX/2;
        D[i].poz=i;
        fv[i]=i;
        w[i]=INT_MAX/2;
    }



    for(i=1;i<=m;i++)
    {
        f>>x>>y>>cost;
        a[x].push_back(y);
        d[x].push_back(cost);
    }

    dijkstra(1);

    for(j=2;j<=n;j++)
        if(w[j]==INT_MAX/2)g<<0<<" ";
    else g<<w[j]<<" ";

    return 0;
}