Cod sursa(job #2295118)

Utilizator tiberiu392Tiberiu Ungurianu tiberiu392 Data 3 decembrie 2018 09:47:46
Problema Algoritmul lui Dijkstra Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.63 kb
#include <fstream>
#include <queue>
#include <vector>
#define Nmax 50005
#define INF 1 << 30

using namespace std;

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

int n, m;
int used[Nmax];
bool in_stack[Nmax];

vector < pair <int,int> > G[Nmax];

struct comp
{
    bool operator()(int x, int y)
    {
        return used[x] > used[y];
    }
};

priority_queue<int, vector<int>, comp> Queue;

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

void dijkstra(int nodStart)
{
    for(int i = 1; i <= n; i++)
        used[i] = INF;

    used[nodStart]=0;

    Queue.push(nodStart);
    in_stack[nodStart] = true;

    while(!Queue.empty())
    {
        int nodCurent = Queue.top();
        Queue.pop();

        in_stack[nodCurent] = false;
        for(size_t i = 0; i < G[nodCurent].size(); i++)
        {
            int neighbor = G[nodCurent][i].first;
            int Cost = G[nodCurent][i].second;
            if(used[nodCurent] + Cost < used[neighbor])
            {
                used[neighbor] = used[nodCurent] + Cost;
                if(in_stack[neighbor] == false)
                {
                    Queue.push(neighbor);
                    in_stack[neighbor] = true;
                }
            }
        }
    }
}

void output()
{
    for(int i = 2; i <= n; i++)
    {
        if(used[i] != INF)
            g << used[i] << " ";
        else
            g << "0 ";
    }
}

int main()
{
    input();
    dijkstra(1);
    output();
}