Cod sursa(job #1172648)

Utilizator johnyJohny Deep johny Data 17 aprilie 2014 20:16:39
Problema Algoritmul lui Dijkstra Scor 40
Compilator cpp Status done
Runda Arhiva educationala Marime 1.45 kb
#include <fstream>
#include <queue>
#define NX 50001
using namespace std;

ifstream fin("dijkstra.in");
ofstream fout("dijkstra.out");

int d[NX],viz[NX],inf=250000001;

struct vecin
{
    int j,c;    //tinem minte nodul vecin si lungimea muchiei
};

struct comp
{
    bool operator() (int a, int b)
    {
        return (d[a] > d[b]);
    }
};

int n,m;
vector<vecin> v[NX];
priority_queue<int, vector<int>, comp> p;

void citire()
{
    int i,a,b,c;
    vecin x;
    fin>>n>>m;
    for(i=1; i<=m; i++)
    {
        fin>>a>>b>>c;
        x.j=b;
        x.c=c;
        v[a].push_back(x);
    }
}

void dijkstra()
{
    int i;
    p.push(1);
    for(i=2; i<=n; i++)
    {
        d[i]=inf;
        p.push(i);
    }
    vector<vecin>::iterator it;
    vecin x;
    int u,r;
    while(!p.empty())
    {
        u = p.top();
        p.pop();
        if(viz[u]==0)
        {
            for(it=v[u].begin();it!=v[u].end();++it)
            {
                x = *it;
                r = d[u] + x.c;
                if(r<d[x.j])
                {
                    d[x.j]=r;
                    p.push(x.j);
                }
            }
            viz[u]=1;
        }
    }
}

int main()
{
    int i;
    citire();
    dijkstra();
    for(i=2; i<=n; i++)
        if(d[i]==inf)
            fout<<0<<' ';
        else
            fout<<d[i]<<' ';

    fin.close();
    fout.close();
    return 0;
}