Cod sursa(job #3264492)

Utilizator BogdancxTrifan Bogdan Bogdancx Data 21 decembrie 2024 18:04:52
Problema Algoritmul lui Dijkstra Scor 0
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.44 kb
#include <vector>
#include <iostream>
#include <fstream>
#include <queue>

using namespace std;

vector<int> Dijkstra(int start, const vector<vector<int>>& graph, const vector<vector<int>>& cost)
{
    // <distanta, nod>
    priority_queue<pair<int, int>, vector<pair<int, int>>, greater<pair<int, int>>> pq;
    vector<int> dist(graph.size(), 1e9);

    dist[start] = 0;
    pq.emplace(0, start);

    while(!pq.empty())
    {
        int node = pq.top().second;
        int d = pq.top().first;
        pq.pop();

        for(int neigh: graph[node])
        {
            int new_d = d + cost[node][neigh];

            if(new_d < dist[neigh])
            {
                dist[neigh] = new_d;
                pq.emplace(new_d, neigh);
            }
        }
    }

    for(int i = 1; i <= graph.size(); i++)
    {
        if(dist[i] == 1e9)
        {
            dist[i] = -1;
        }
    }

    return dist;
}

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

    int n, m;

    fin >> n >> m;

    vector<vector<int>> graph(n + 1);
    vector<vector<int>> cost(n + 1, vector<int>(n + 1, 0));

    int a, b, w;
    while(fin >> a >> b >> w)
    {
        graph[a].push_back(b);
        cost[a][b] = w;
    }

    vector<int> result = Dijkstra(m, graph, cost);

    for(int i = 2; i < result.size(); i++)
    {
        fout << result[i] << ' ';
    }

    return 0;
}