Cod sursa(job #2693165)

Utilizator MevasAlexandru Vasilescu Mevas Data 5 ianuarie 2021 00:19:20
Problema Algoritmul lui Dijkstra Scor 50
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.36 kb
#include <iostream>
#include <vector>
#include <fstream>
#include <climits>
#include <queue>

#define Nmax 50010

using namespace std;

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

int n, m;
vector<pair<int, int>> graph[Nmax];
bool alreadyInQueue[Nmax];

void solve(int startNode) {
    priority_queue<pair<int, int>> pq;
    vector<int> distances(n + 1, INT_MAX);

    pq.emplace(0, startNode);
    distances[startNode] = 0;

    while(!pq.empty()) {
        auto vertex = pq.top().second;
        pq.pop();
        alreadyInQueue[vertex] = false;

        for(auto pair : graph[vertex]) {
            int current = pair.first;
            int weight = pair.second;

            if(distances[current] > distances[vertex] + weight) {
                distances[current] = distances[vertex] + weight;
                if (!alreadyInQueue[current]) {
                    pq.emplace(distances[current], current);
                }
                alreadyInQueue[current] = true;
            }
        }
    }

    for(int i = 2; i <= n; i++) {
        fout << (distances[i] == INT_MAX ? 0 : distances[i]) << " ";
    }
}

int main() {
//    reading
    fin >> n >> m;
    for(int i = 0; i < m; i++) {
        int x, y, weight;
        fin >> x >> y >> weight;
        graph[x].emplace_back(y, weight);
    }

    solve(1);
}