Cod sursa(job #1841406)

Utilizator BugirosRobert Bugiros Data 5 ianuarie 2017 16:55:42
Problema Drumuri minime Scor 25
Compilator cpp Status done
Runda Arhiva de probleme Marime 2.21 kb
#include <fstream>
#include <cmath>
#include <queue>
#include <vector>
#include <limits>
using namespace std;

const int MAXN = 1502;
const int MODULO = 104659;
const double EPSILON = 1e-10;

ifstream in("dmin.in");
ofstream out("dmin.out");

int n;
vector<int> vecini[MAXN];
vector<double> cost[MAXN];


struct nod_dijk
{
    int nod;
    double dist;
    bool operator < (const nod_dijk b) const
    {
        return dist > b.dist;//heap de maxime
    }
};

priority_queue<nod_dijk> heap;

void citire()
{
    int m;
    in >> n >> m;
    for (int i = 1;i <= m;++i)
    {
        int a, b, c;
        in >> a >> b >> c;

        vecini[a].push_back(b);
        cost[a].push_back(log((double)c));
        //logaritmam costurile deoarece ne putem folosi de proprietatea
        //log a + log b = log(a + b)
        vecini[b].push_back(a);
        cost[b].push_back(log((double)c));
    }
}

double d[MAXN];
int p[MAXN];

void dijkstra()
{
    for (int i = 0;i < MAXN;++i)
    {
        d[i] = numeric_limits<double>::max();
        p[i] = 0;
    }
    heap.push((nod_dijk){1,0});
    d[1] = 0;
    p[1] = 1;
    while(!heap.empty())
    {
        int nod = heap.top().nod;
        double dist = heap.top().dist;
        heap.pop();
        if(abs(d[nod] - dist) > EPSILON)
            continue;
        p[nod] = 0;
        for(unsigned int i = 0;i < vecini[nod].size();++i)
        {
            int vecin = vecini[nod][i];
            double c = cost[nod][i];
            if (d[vecin] == numeric_limits<double>::max())
                continue;
            if (abs(d[vecin] + c - d[nod]) <= EPSILON)
                p[nod] += p[vecin];
        }
        if(p[nod] == 0)
            p[nod] = 1;

        for(unsigned int i = 0;i < vecini[nod].size();++i)
        {
            int vecin = vecini[nod][i];
            double c = cost[nod][i];
            if (d[nod] + c < d[vecin])
            {
                d[vecin] = d[nod] + c;
                heap.push((nod_dijk){vecin, d[vecin]});
            }
        }
    }
}

int main()
{
    citire();
    dijkstra();
    for (int i = 2;i <= n;++i)
        out << p[i] << ' ';
    out << '\n';
    return 0;
}