Cod sursa(job #1878159)

Utilizator FlowstaticBejan Irina Flowstatic Data 13 februarie 2017 21:48:00
Problema Algoritmul lui Dijkstra Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.28 kb
#include <fstream>
#include <vector>
#include <cstring>
#include <queue>
#include <utility>
#define INF 1<<30
#define FOR(i,a,b) for(int i = a; i<=b;i++)
#define NMAX 50005
using namespace std;

ifstream fin("dijkstra.in");
ofstream fout("dijkstra.out");

vector<pair<int,int> > G[NMAX];
priority_queue< pair<int, int>, vector<pair<int,int> >, greater<pair<int,int> > > Q;
int d[NMAX];
int N,M;

void Dijkstra(int x);

int main()
{
    fin>>N>>M;
    int a,b,c;
    FOR(i,1,M)
    {
        fin>>a>>b>>c;
        G[a].push_back(make_pair(b,c));
    }
    Dijkstra(1);

    FOR(i,2,N)
    {
        if(d[i]!=INF)
            fout<<d[i]<<" ";
        else
            fout<<"0"<<" ";
    }
    fout<<'\n';
    return 0;
}

void Dijkstra(int x)
{
    FOR(i,1,N)
        d[i] = INF;
    d[x] = 0;
    Q.push(make_pair(0,x));
    while(!Q.empty())
    {

        pair<int, int> nod = Q.top();
        Q.pop();

        if(nod.first != d[nod.second])
            continue;

        for(int i = 0; i< G[nod.second].size(); i++)
        {
            int vec = G[nod.second][i].first;
            int cost = G[nod.second][i].second;

            if(d[vec] > d[nod.second]+cost)
            {
                d[vec] = d[nod.second]+cost;
                Q.push(make_pair(d[vec],vec));
            }
        }
    }
}