Cod sursa(job #2812256)

Utilizator rARES_4Popa Rares rARES_4 Data 4 decembrie 2021 11:51:28
Problema Algoritmul lui Dijkstra Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.45 kb
#include <iostream>
#include <fstream>
#include <set>
#include <vector>
#include<climits>
using namespace std;
ifstream f ("dijkstra.in");
ofstream g ("dijkstra.out");
int n,m,x,y,c;
bool viz[50001];
vector<pair<int,int>>adiacenta[50001];
int costuri[50001];
set<pair<int,int>> s;
void citire()
{
    f >> n >> m;
    for(int i = 1; i<=m; i++)
    {
        f >> x >> y >> c;
        adiacenta[x].push_back({y,c});
    }
    for(int i = 1; i<=50000; i++)
        costuri[i] = INT_MAX;
}
void alg()
{
    costuri[1] = 1;
    s.insert({1,1});
    while(!s.empty())
    {
        int nod = s.begin()->second;
        int cost = s.begin()->first;
        s.erase(s.begin());
        for(auto x:adiacenta[nod])
        {
            if(costuri[x.first]>x.second+cost)
            {
                //daca deja l-am modificat
                // inseamna ca deja i am pus valoarea minima asa ca stergem daca mai exista un alt nod la fel
                if(costuri[x.first]!=INT_MAX)
                    s.erase(s.find({costuri[x.first],x.first}));
                costuri[x.first]=x.second+cost;
                s.insert({costuri[x.first],x.first});
            }
        }
    }
}
void afisare()
{
    for(int i = 2; i<=n; i++)
    {
        if (costuri[i] == INT_MAX)
        {
            g << 0 << " ";
        }
        else
            g << costuri[i]-1<< " ";
    }
}
int main()
{
    citire();
    alg();
    afisare();
}