Cod sursa(job #2812225)

Utilizator George_CristianGeorge Dan-Cristian George_Cristian Data 4 decembrie 2021 11:11:29
Problema Algoritmul lui Dijkstra Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.21 kb
#include <fstream>
#include <queue>
#include <vector>

using namespace std;

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

#define NMAX 50005
#define INF ((1<<30)-1)

int n, m, d[NMAX], prec[NMAX];
bool viz[NMAX];
vector<pair<int, int>> G[NMAX];
priority_queue<pair<int, int>, vector<pair<int, int>>, greater<>> q;

void citire() {
    f >> n >> m;
    int a, b, c;
    for (int i = 1; i <= m; ++i) {
        f >> a >> b >> c;
        G[a].push_back({b, c});
    }
}

void initializare() {
    for (int i = 1; i <= n; ++i)
        d[i] = INF;
}

void vizitare_nod(int x) {
    viz[x] = true;
    for (auto &nod: G[x])
        if (d[x] + nod.second < d[nod.first]) {
            d[nod.first] = d[x] + nod.second;
            q.push({d[nod.first], nod.first});
        }
}

void dijkstra() {
    d[1] = 0;
    q.push({0, 1});
    while (!q.empty()) {
        int nod = q.top().second;
        q.pop();
        if (viz[nod])
            continue;
        vizitare_nod(nod);
    }
}

void afisare() {
    for (int i = 2; i <= n; ++i) {
        if (d[i] == INF)
            g << 0 << ' ';
        else
            g << d[i] << ' ';
    }
}

int main() {
    citire();
    initializare();
    dijkstra();
    afisare();
    return 0;
}