Cod sursa(job #2961528)

Utilizator maiaauUngureanu Maia maiaau Data 6 ianuarie 2023 17:11:46
Problema Algoritmul lui Dijkstra Scor 0
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.26 kb
#include <fstream>
#include <set>
#include <utility>
#include <vector>
using namespace std;

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

const int N = 5e4 + 5;
const int oo = 2e9;

int n, m, x, y, vf, c, cost[N][N], cmn[N];
vector<int> ad[N];
set<pair<int, int>> s;

void init(), dijkstra();
inline void prt();

int main()
{
    init();
    dijkstra();
    prt();
    return 0;
}

void init() {
    f >> n >> m;
    for (; m; m--) {
        f >> x >> y >> c;
        cost[x][y] = c;
        ad[x].push_back(y);
    }
    for (int i = 1; i <= n; i++){
        cmn[i] = oo;
        for (int j = 1; j <= n; j++)
            if (i != j && cost[i][j] == 0) cost[i][j] = oo;
    }
}
inline void prt() {
    for (int i = 2; i <= n; i++)
        g << (cmn[i] == oo ? 0 : cmn[i]) << ' ';
}
void dijkstra() {
    cmn[1] = 0;
    s.insert({ 0, 1 });
    while (!s.empty()) {
        c = s.begin()->first;
        vf = s.begin()->second;
        s.erase({ c, vf });
        for (auto it : ad[vf]) {
            int aux = c + cost[vf][it];
            if (aux < cmn[it]) {
                if (cmn[it] != oo) s.erase({ aux, it });
                cmn[it] = aux;
                s.insert({ aux, it });
            }
        }
    }
}