Cod sursa(job #2175758)

Utilizator raul044Moldovan Raul raul044 Data 16 martie 2018 18:52:46
Problema Algoritmul lui Dijkstra Scor 20
Compilator cpp Status done
Runda Arhiva educationala Marime 1.22 kb
#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
#define inf 0x3f3f3f3f
#define maxN 50005

using namespace std;

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

int n, m, D[maxN], viz[maxN];
vector <pair <int, int> > G[maxN];
priority_queue <pair <int, int> > Q;

void initD () {
    for (int i = 1; i <= n; ++i) {
        D[i] = inf;
    }
}

void Dijkstra (int nod) {
    D[nod] = 0;
    Q.push({0, 1});
    while (!Q.empty()) {
        int x = Q.top().second;
        Q.pop();
        if (!viz[x]) {
            viz[x]++;
            int size = G[x].size();
            for (int i = 0; i < size; ++i) {
                int y = G[x][i].second, w = G[x][i].first;
                if (D[y] > D[x] + w) {
                    D[y] = D[x]+ w;
                    Q.push({-D[y], y});
                }
            }
        }
    }
    for (int i = 2; i <= n; ++i) {
        if (D[i] == inf)
            fout << -1 << " ";
        else
            fout << D[i] << " ";
    }
}

int main () {
    fin >> n >> m;
    int x, y, w;
    for (int i = 1; i <= m; ++i) {
        fin >> x >> y >> w;
        G[x].push_back({w, y});
    }
    initD();
    Dijkstra(1);
}