Cod sursa(job #2802163)

Utilizator NadiraBodrogean Nadira Nadira Data 17 noiembrie 2021 17:45:21
Problema Algoritmul Bellman-Ford Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.3 kb
#include <fstream>
#include <queue>
#include <vector>
using namespace std;
ifstream cin("bellmanford.in");
ofstream cout("bellmanford.out");
int n,m;
const int Nmax=50005,oo=(1<<30);
queue <int>Q;
vector<pair<int,int>>G[Nmax];
int D[Nmax];
bool incoada[Nmax];
int ap[Nmax];
void citire()
{
    int i,x,y,c;
    cin>>n>>m;
    for(i=1;i<=m;i++)
    {
        cin>>x>>y>>c;
        G[x].push_back(make_pair(y,c));
    }
}
bool bellmanford(int s)
{
    int i;
    for(i=1;i<=n;i++)
        D[i]=oo;
    D[s]=0;
    Q.push(s);
    incoada[s]=true;
    while(!Q.empty())
    {
        int x=Q.front();
        Q.pop();
        incoada[x]=false;
        ap[x]++;
        if(ap[x]>n)
            return false;
        for(size_t i=0;i<G[x].size();i++)
        {
            int vecin=G[x][i].first;
            int cost=G[x][i].second;
            if(D[x]+cost<D[vecin])
            {
                D[vecin]=D[x]+cost;
                if(incoada[vecin]==false)
                {
                    incoada[vecin]=true;
                    Q.push(vecin);
                }
            }
        }
    }
    return true;
}
int main()
{int i;
citire();
if(bellmanford(1))
{
    for(i=2;i<=n;i++)
        cout<<D[i]<<' ';
}
else
    cout<<"Ciclu negativ!";
    return 0;
}