Cod sursa(job #2930103)

Utilizator andreii254andrei andreii254 Data 27 octombrie 2022 15:02:46
Problema Algoritmul lui Dijkstra Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.32 kb
#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
#include <bitset>

using namespace std;

const int N = 5e4 + 1;

vector <pair<int, int>> L[N];
vector<int> dist;
bitset<N> vis;
priority_queue< pair<int, int>, vector<pair <int, int> >, greater<pair<int, int> > > pq;
int n;

void Read()
{
    ifstream fin ("dijkstra.in");
    int m;
    fin >> n >> m;
    while(m--)
    {
        int x, y, c;
        fin >> x >> y >> c;
        L[x].push_back({y, c});
    }
    fin.close();
}

void Dijkstra()
{
    dist.resize(n + 1, 2e9);
    dist[1] = 0;
    pq.push({0, 1});
    while (!pq.empty())
    {
        pair <int, int> curr = pq.top(); // curr.first = distanta, curr.second = nod
        pq.pop();
        if (!vis[curr.second]) {
            vis[curr.second] = 1;
            for (auto &next: L[curr.second]) //next.first = nod adiacent, next.second = costul muchiei pana la next.first
                if (dist[next.first] > next.second + curr.first) {
                    dist[next.first] = next.second + curr.first;
                    pq.push({dist[next.first], next.first});
                }
        }
    }
    ofstream fout ("dijkstra.out");
    for (int i = 2; i <= n; i++)
        (dist[i] == 2e9) ? fout << "0 " : fout << dist[i] << " ";
    fout.close();
}

int main() {
    Read();
    Dijkstra();
    return 0;
}