Cod sursa(job #2737886)

Utilizator Mihai_EduardMihai Eduard Mihai_Eduard Data 5 aprilie 2021 11:41:26
Problema Algoritmul lui Dijkstra Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.44 kb
#include <bits/stdc++.h>

#define MX 50001
#define inf 2000000000

using namespace std;

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

int n, m, d[MX];
vector<pair<int,int>> v[MX];
set<pair<int,int>> s;
bool in[MX];

void citire()
{
    fin>>n>>m;
    int x, y, z;
    for(int i=1;i<=m;i++)
    {
        fin>>x>>y>>z;
        v[x].push_back({y,z});
    }
    fin.close();
}

void Dijkstra()
{
    for(int i=2;i<=n;i++)
        d[i]=inf;
    d[1]=0;
    s.insert({d[1],1});
    in[1]=true;
    while(!s.empty())
    {
        auto it=s.begin();
        in[it->second]=false;
        for(auto x: v[it->second])
        {
            if(d[x.first]>d[it->second]+x.second)
            {
                int last=d[x.first];
                d[x.first]=d[it->second]+x.second;
                if(in[x.first]==false)
                {
                    s.insert({d[x.first],x.first});
                    in[x.first]=true;
                }
                else
                {
                    s.erase({last,x.first});
                    s.insert({d[x.first],x.first});
                }
            }
        }
        s.erase(it);
    }
}

void afisare()
{
    for(int i=2;i<=n;i++)
    {
        if(d[i]==inf)
            fout<<0<<' ';
        else
            fout<<d[i]<<' ';
    }
    fout.close();
}

int main()
{
    citire();
    Dijkstra();
    afisare();
    return 0;
}