Cod sursa(job #1174141)

Utilizator pop_bogdanBogdan Pop pop_bogdan Data 22 aprilie 2014 01:30:14
Problema Algoritmul lui Dijkstra Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.33 kb
#include <fstream>
#include <queue>
#include <vector>
using namespace std;

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

vector<pair<int,int> > V[50001];
priority_queue< pair<int,int>, vector<pair<int,int> >, greater<pair<int,int> > > P;
int N, M, R[50001];

void Input();
void Dijkstra();
void Output();

int main()
{
    Input();
    Dijkstra();
    Output();

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

void Input()
{
    int a, b, c;
    is >> N >> M;
    for ( int i = 2; i <= N; ++i )
        R[i] = 0x3f3f3f3f;
    for ( int i = 1; i <= M; ++i )
    {
        is >> a >> b >> c;
        V[a].push_back(make_pair(b,c));
    }
}

void Dijkstra()
{
    P.push(make_pair(0,1));
    int x, c;
    while ( !P.empty() )
    {
        c = P.top().first;
        x = P.top().second;
        P.pop();
        vector <pair<int,int> > :: iterator it;
        for ( it = V[x].begin(); it != V[x].end(); ++it )
            if ( R[it->first] > c + it->second )
            {
                R[it->first] = c + it->second;
                P.push(make_pair(c + it->second,it->first));
            }
    }
}

void Output()
{
    for ( int i = 2; i <= N; ++i )
    {
        if ( R[i] != 0x3f3f3f3f )
            os << R[i] << " ";
        else
            os << 0 << " ";
    }
}