Cod sursa(job #1854898)

Utilizator eduardturtoiEduard Turtoi eduardturtoi Data 23 ianuarie 2017 12:18:13
Problema Algoritmul lui Dijkstra Scor 0
Compilator cpp Status done
Runda Arhiva educationala Marime 1.29 kb
#include <fstream>
#include <utility>
#include <vector>
#include <set>
#define nmax 50005
#define inf 0x3f3f3f3f
using namespace std;
ifstream fin("dijkstra.in");
ofstream fout("dijkstra.out");
set<pair<int,int> >heap;
vector<pair<int,int> >a[nmax];
vector<pair<int,int> >::iterator it;
int n,m,d[nmax];

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

void dijkstra()
{
    int i,c,nod,next;
    for(i=1;i<=n;i++)
        d[i]=inf;
    d[1]=0;
    heap.insert(make_pair(1,0));
    while(!heap.empty())
    {
        nod=heap.begin()->first;
        c=heap.begin()->second;
        heap.erase(heap.begin());
        for(it=a[nod].begin();it!=a[nod].end();it++)
        {
            next=it->first;
            c=it->second;
            if(d[next]>d[nod]+c)
            {
                if(d[next]!=inf)
                    heap.erase(heap.find(make_pair(next,d[next])));
                d[next]=d[nod]+c;
                heap.insert(make_pair(next,d[next]));
            }
        }
    }
    for(i=2;i<=n;i++)
    {
        if(d[i]==inf)
            d[i]=0;
        fout<<d[i]<<" ";
    }
}

int main()
{
    citire();
    dijkstra();
    return 0;
}