Cod sursa(job #2360546)

Utilizator nurof3nCioc Alex-Andrei nurof3n Data 1 martie 2019 21:55:20
Problema Algoritmul lui Dijkstra Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.52 kb
//NU MERGE PENTRU ARCE DE COST NEGATIV!!


#include <fstream>
#include <cstdio>
#include <queue>
#include <vector>

using namespace std;

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

const int MAX = 50001;

struct comp {
    bool operator() (const pair<int, int> &a, const pair<int, int> &b) {
        return a.second > b.second;
    }
};
priority_queue<pair<int, int>, vector<pair<int, int>>, comp> Q;
vector<pair<int, int>> G[MAX];

int D[MAX];  //retine costul minim al drumului pana la fiecare nod, care trece doar prin nodurile vizitate
int N, M;

void dijkstra() {
    while (!Q.empty()) {
        int x = Q.top().first;
        int d = Q.top().second;
        Q.pop();
        if(D[x] < d)
            continue;
        for (auto m : G[x]) {
            int y = m.first;
            int cost = m.second;
            if (D[x] + cost < D[y]) {
                D[y] = D[x] + cost;
                Q.push ({y, D[y]});
            }
        }
    }
}

int main() {

    int x, y, cost;
    in >> N >> M;
    for (int i = 1; i <= N; i++)
        D[i] = 1000000;
    D[1] = 0;
    for (int i = 1; i <= M; i++) {
        in >> x >> y >> cost;
        G[x].push_back (pair<int, int> (y, cost));
        if(x == 1) {
            D[y] = cost;
            Q.push (pair<int, int> (y, D[y]));
        }
    }

    dijkstra();

    for (int i = 2; i <= N; i++)
        if (D[i] < 1000000)
            out << D[i] << ' ';
        else
            out << 0 << ' ';

    return 0;
}