Cod sursa(job #1774205)

Utilizator LaurIleIle Laurentiu Daniel LaurIle Data 8 octombrie 2016 18:01:29
Problema Algoritmul lui Dijkstra Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.42 kb
#include <iostream>
#include <vector>
#include <queue>
#include <fstream>
#define INF 2000000000
#define nmax 50002
using namespace std;

vector <pair <int, int> > G[nmax];
int tata[nmax], dmin[nmax], n, m;

class compar
{
public:
    bool operator () (const int &x, const int &y)
    {
        return dmin[x]>dmin[y];
    }
};

priority_queue <int, vector <int>, compar> q;

void read()
{
    ifstream f("dijkstra.in");
    f >> n >> m;
    for(int i=0, x, y, c; i<m; ++i)
    {
        f >> x >> y >> c;
        G[x].push_back(make_pair(y,c));
    }
    f.close();
}

void dijkstra()
{
    vector <pair <int, int> > :: iterator it;
    int i, x;
    q.push(1);
    for(i=1; i<=n; ++i)
    {
        dmin[i]=INF;
        tata[i]=1;
    }
    tata[1]=0; dmin[1]=0;
    while(!q.empty())
    {
        x=q.top(); q.pop();
        for(it=G[x].begin(); it!=G[x].end(); ++it)
        {
            if(dmin[it->first] > dmin[x] + it->second)
            {
                dmin[it->first] = dmin[x] + it->second;
                q.push(it->first);
                tata[it->first]=x;
            }
        }
    }
}

void out()
{
    ofstream g("dijkstra.out");
    for(int i=2; i<=n; ++i)
        if(dmin[i]!=INF)
        g << dmin[i] << ' ';
        else
        g << 0 << ' ';
    g << '\n';
    g.close();
}

int main()
{
    read();
    dijkstra();
    out();
    return 0;
}