Cod sursa(job #1919965)

Utilizator filip.mihalutMihalut Filip filip.mihalut Data 9 martie 2017 21:47:08
Problema Algoritmul lui Dijkstra Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.27 kb
#include <iostream>
#include <fstream>
#include <vector>
#include <set>
#include <cstring>
#define inf 0x3f3f3f3f

using namespace std;

ifstream f ("dijkstra.in");
ofstream g ("dijkstra.out");

vector < pair < int,int > > v[50002];
vector < pair < int,int > > :: iterator it;
set < pair < int,int > > heap;
int n,m,x,y,c,i,nod,next_nod,dist[50002];

int main()
{
    f >> n >> m;

    for(i = 1; i <= m; i++)
    {
        f >> x >> y >> c;
        v[x].push_back({y,c});
    }

    memset(dist, inf , sizeof(dist));
    dist[1] = 0;
    heap.insert({0 , 1});

    while(not heap.empty())
    {
        nod = heap.begin() -> second;
        heap.erase(heap.begin());

        for(it = v[nod].begin(); it != v[nod].end(); it++)
        {
            next_nod = it -> first;
            c = it -> second;
            if(dist[next_nod] > dist[nod] + c)
            {
                if(dist[next_nod] != inf)
                    heap.erase(heap.find({dist[next_nod], next_nod}));
                dist[next_nod] = dist[nod] + c;
                heap.insert({dist[next_nod], next_nod});
            }
        }
    }

    for(i = 2; i <= n; i++)
        if(dist[i] == inf)
            g << 0 << " ";
        else g << dist[i] << " ";
    return 0;
}