Cod sursa(job #1547710)

Utilizator BaweeLazar Vlad Bawee Data 9 decembrie 2015 19:26:24
Problema Algoritmul lui Dijkstra Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.33 kb
#include <fstream>
#include <algorithm>
#include <vector>


#define pp pair<int,int>

using namespace std;

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

const int MaxN = 50001;
const int INF = 1 << 30;

vector < pair < int , int > > G[MaxN];
vector <int> heap;
int d[MaxN],n,m;

bool cmp(const int& a, const int& b)
{
    return d[a] > d[b];
}

int main()
{
    int x,y,c;

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

    int source = 1;
    for(int i = 2; i <= n; i++) d[i] = INF;
    d[source] = 0;

    heap.push_back(source);
    make_heap(heap.begin(),heap.end(),cmp);

    while(heap.size())
    {
        int node = heap.front();
        pop_heap(heap.begin(),heap.end(),cmp);
        heap.pop_back();

        for(vector<pp>::iterator it = G[node].begin(); it != G[node].end(); ++it)
        {
            int newNode = it -> first;
            int newNodeCost = it -> second;
            if(d[newNode] > d[node] + newNodeCost)
            {
                d[newNode] = d[node] + newNodeCost;
                heap.push_back(newNode);
                push_heap(heap.begin(),heap.end(),cmp);
            }
        }
    }
    for(int i = 2; i <= n; ++i)
        g << (d[i] < INF ? d[i] : 0) << " ";
}