Cod sursa(job #2712144)

Utilizator Fatu_SamuelFatu Samuel Fatu_Samuel Data 25 februarie 2021 11:34:37
Problema Algoritmul lui Dijkstra Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.55 kb
#include <iostream>
#include <fstream>
#include <vector>
#include <bitset>
#include <queue>

using namespace std;

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

const int nMax = 50005;
const int inf = (1 << 30);

struct Node 
{
    int next, w;
};


int n, m;
int dist[nMax];
vector < Node > l[nMax];
bitset < nMax > viz;

struct comp
{
    bool operator() (int a, int b)
    {
        return (dist[a] > dist[b]);
    }
};

priority_queue < int, vector < int >, comp > q;

void Dijkstra (int node)
{
    for (int i = 2; i <= n; i++)
    {
        dist[i] = inf;
    }

    q.push(node);
    viz[node] = 1;

    while (!q.empty())
    {
        node = q.top();
        q.pop();

        viz[node] = 0;

        for (Node nextNode : l[node])
        {
            if (dist[nextNode.next] > dist[node] + nextNode.w)
            {
                dist[nextNode.next] = dist[node] + nextNode.w;

                if (!viz[nextNode.next])
                {
                    viz[nextNode.next] = 1;
                    q.push(nextNode.next);
                }
            }
        }
    }
}

int main()
{
    fin >> n >> m;

    for (int i = 1; i <= m; i++)
    {
        int a, b, w;

        fin >> a >> b >> w;

        l[a].push_back({b, w});
    }

    Dijkstra(1);

    for (int i = 2; i <= n; i++)
    {
        if (dist[i] == inf)
        {
            dist[i] = 0;
        }
        
        fout << dist[i] << ' ';
    }

    fin.close();
    fout.close();
    return 0;
}