Nu aveti permisiuni pentru a descarca fisierul grader_test9.in

Cod sursa(job #1371409)

Utilizator koroalinAlin Corodescu koroalin Data 3 martie 2015 21:19:59
Problema Algoritmul lui Dijkstra Scor 50
Compilator cpp Status done
Runda Arhiva educationala Marime 1.52 kb
#include <cstdio>
#include <vector>
#include <queue>
#define NMAX 50001
#define INF 1<<30
using namespace std;
FILE* fin=fopen("dijkstra.in","r");
FILE* fout=fopen("dijkstra.out","w");
int n,m,dist[NMAX];
vector <pair <int,int> > G[NMAX];
struct comp
{
     bool operator()(pair <int,int> a , pair <int,int> b){return a.second<b.second;}
};
priority_queue < pair<int,int>,vector<pair <int,int> >,comp> pq;
void citire();
void dijkstra();
int main()
{
    citire();
    dijkstra();
    return 0;
}
void citire()
{
    int i,a,b,c;
    fscanf (fin,"%d %d",&n,&m);
    for (i=1; i<=m; i++)
    {
        fscanf( fin,"%d %d %d",&a,&b,&c);
        G[a].push_back(make_pair(b,c));
    }
}
void dijkstra()
{
    int i,nod,cost;
    bool ok;
    for (i=1; i<=n; i++) dist[i]=INF;
    dist[1]=0;
    pq.push(make_pair(1,0));
    while (!pq.empty())
    {
        do
        {
            ok=1;
            nod=pq.top().first; cost=pq.top().second;
            pq.pop();
            if (dist[nod]!=cost) ok=0;
        }
        while (ok==0);
        for (i=0; i<G[nod].size(); i++)
        {
            if (dist[G[nod][i].first]> dist[nod] + G[nod][i].second)
            {
                dist[G[nod][i].first]=dist[nod] + G[nod][i].second;
                pq.push( make_pair( G[nod][i].first,dist[G[nod][i].first]));
            }
        }
    }
    for (i=2; i<=n; i++)
    {
        if (dist[i]!=INF) fprintf(fout,"%d ",dist[i]);
        else fprintf(fout,"0 ");
    }
    fprintf(fout,"\n");
}