Cod sursa(job #1072441)

Utilizator macajouMaca George macajou Data 4 ianuarie 2014 14:20:06
Problema Algoritmul lui Dijkstra Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.71 kb
#include <cstdio>
#include <queue>
#include <vector>
#define inf 1<<30
#define nmax 50010

using namespace std;

struct vecini
{
    int vec,c;
};

vector<vecini> v[nmax];
int n,m,cost[nmax],prezent[nmax];

void citire()
{
    int i,x;
    vecini vc;
    scanf("%d%d",&n,&m);
    for(i=1;i<=m;i++)
        {
            scanf("%d%d%d",&x,&vc.vec,&vc.c);
            v[x].push_back(vc);
        }
    for(i=2;i<=n;i++)
        cost[i]=inf;
}

struct cmp
{
    bool operator()(const int& a, const int& b)
    {
        return cost[a]>cost[b];
    }
};

void dijkstra()
{
    priority_queue<int,vector<int>,cmp> q;
    q.push(1);
    prezent[1]=1;
    int p,i,vc,c,cc;
    while(!q.empty())
          {
              p=q.top();
              q.pop();
              for(i=0;i<v[p].size();i++)
                  {
                      vc=v[p][i].vec;
                      c=v[p][i].c;
                      cc=cost[p]+c;
                      if(cc<cost[vc])
                         {
                             cost[vc]=cc;
                             if(!prezent[vc])
                                 {
                                     q.push(vc);
                                     prezent[vc]=1;
                                 }
                         }
                  }
                prezent[p]=0;
          }
}

void afisare()
{
    int i;
    for(i=2;i<=n;i++)
        {
            if(cost[i]==inf)
               printf("0 ");
            else printf("%d ",cost[i]);
        }
}

int main()
{
    freopen("dijkstra.in","r",stdin);
    freopen("dijkstra.out","w",stdout);

    citire();
    dijkstra();
    afisare();

    return 0;
}