Cod sursa(job #2681343)

Utilizator miramaria27Stroie Mira miramaria27 Data 5 decembrie 2020 11:51:32
Problema Algoritmul lui Dijkstra Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.68 kb
#include <iostream>
#include <vector>
#include <algorithm>
#include <fstream>
#include <utility>
#include <list>
#include <queue>
#include <functional>
using namespace std;

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

int inf = 100000;
priority_queue<pair<int,int>,vector<pair<int,int>>,greater<pair<int,int>>> q;
int n,m;
int tata[50001],viz[50001],dist[50001];
list <pair<int,int>> ad[50001];
int s, length;
void initialize()
{
    s = 1;
    for(int i = 1; i <= n; i ++)
    {

        tata[i] = 0;
        viz[i] = 1;
        dist[i] = inf;
    }
    q.push(make_pair(0,s));
    dist[s] = 0;
}
int main()
{
    fin >> n >> m;
    for( int i = 1; i <= m ; i++)
    {
        int a,b,c;
        fin >> a >> b >> c;
        ad[a].push_back(make_pair(b,c));
    }
    ///initializam nodul de start si costul arborelui
    initialize();
    while(!q.empty())
    {
        ///gasim nodul
        pair <int,int> least = q.top();
        int node = least.second;
        ///"stergem" nodul
        q.pop();
        ///evitam ciclurile
        if(viz[node] == 0)
            continue;
        viz[node] = 0;
        /// actualizam vectorul dist si tata pentru vecinii lui node
        for(auto &edge: ad[node])
        {
            if(dist[edge.first] > edge.second + dist[node])
            {
                dist[edge.first] = edge.second + dist[node];
                tata[edge.first] = node;
                q.push(make_pair(dist[edge.first],edge.first));
            }
        }
    }
    for(int i = 2; i <=n ; i++)
        if(dist[i] == inf)
            fout<<0<<" ";
        else
            fout<<dist[i]<<" ";
    return 0;
}