Cod sursa(job #3142768)

Utilizator vladsipunct5555Butnrau Vlad vladsipunct5555 Data 24 iulie 2023 13:04:44
Problema Algoritmul lui Dijkstra Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.29 kb
#include <iostream>
#include <set>
#include <vector>
#include <map>
#include <fstream>

using namespace std;

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

map <int, int> fr;
set <pair<int, int>> d;
vector <pair <int, int>> v[50001];
int n, m;
int c[50001];

void Dijkstra() {



    while (!d.empty()) {
        pair<int, int> nod = *d.begin();
        d.erase(d.begin());

        for (auto vecin : v[nod.second])
            if (c[vecin.first] == -1) {
                d.insert({nod.first + vecin.second, vecin.first});
                c[vecin.first] =  nod.first + vecin.second;
            } else if (nod.first + vecin.second < c[vecin.first]) {
                d.erase({c[vecin.first], vecin.first});
                c[vecin.first] = nod.first + vecin.second;
                d.insert({nod.first + vecin.second, vecin.first});
            }

    }
}

int main() {
    fin >> n >> m;
    for (int i = 1; i <= m; i ++) {
        int a, b, c;
        fin >> a >> b >> c;
        v[a].push_back({b, c});
    }

    for (int i = 0; i <= n; i ++)
        c[i] = -1;

    int s = 1;
    c[s] = 0;

    d.insert({0, s});
    fr[s] = 1;
    Dijkstra();

    for (int i = 2; i <= n; i ++)
        if (c[i] != -1)
            fout << c[i] << " ";
        else
            fout << 0 << " ";

    return 0;
}