Cod sursa(job #1597916)

Utilizator killlerr1Chilom Mircea killlerr1 Data 12 februarie 2016 14:44:09
Problema Algoritmul lui Dijkstra Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.53 kb
#include <fstream>
#include <vector>
#include <queue>
using namespace std;

ifstream is("dijkstra.in");
ofstream os("dijkstra.out");


const int MAXN = 50001, INF = 1 << 30;


struct Edge{
    int node, cost;
    const bool operator <( const Edge& e) const
    {
        return cost > e.cost;
    }
};

priority_queue <Edge> Q;

typedef vector<int> VI;
vector<vector<Edge> > G;
bool vis[MAXN];
int dmin[MAXN];
int n;
int m;

void Read();
void Dijkstra(int nod);
void Write();


int main()
{
    Read();
    Dijkstra(1);
    Write();

    is.close();
    os.close();
    return 0;
}

void Read()
{
    int a, b, c;
    is >> n;
    G.resize(n+1);
    is >> m;
    for( int i = 1; i <= m; ++i )
    {
        is >> a >> b >> c;
        G[a].push_back({b, c});
    }
}

void Write()
{
    for( int i = 2; i <= n; ++i )
    {
        if( dmin[i] == INF )
            os << '0' << ' ';
        else
            os << dmin[i] << ' ';
    }
}

void Dijkstra(int nod)
{
    for( int i = 1; i <= n; ++i )
        dmin[i] = INF;
    dmin[1] = 0;
    Q.push({nod, 0});

    while(!Q.empty())
    {
        nod = Q.top().node;
        vis[nod] = true;

        for( auto e : G[nod] )
        {
            if( !vis[e.node] && dmin[nod] + e.cost < dmin[e.node] )
            {
                dmin[e.node] = e.cost + dmin[nod];
                Q.push({e.node, dmin[e.node]});
            }
        }

        while( !Q.empty() && vis[Q.top().node] )
            Q.pop();

    }


}