Cod sursa(job #2888304)

Utilizator raul41917raul rotar raul41917 Data 10 aprilie 2022 22:25:42
Problema Algoritmul Bellman-Ford Scor 95
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.66 kb
#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
#define INF 2147483647
using namespace std;
ifstream fi("bellmanford.in");
ofstream fo("bellmanford.out");
int n,m;
vector <pair<int,int> >V[50005];
queue <pair<int,int> >coada;
int D[50005];
bool apare[50005];
int noD[50005];
void BellmanFordMoore(int vertex)
{
    coada.push(make_pair(0,vertex));
    int negativeCycle=0;
    while(!coada.empty() && !negativeCycle)
    {
        int node=coada.front().second;
        int d=coada.front().first;
        coada.pop();
        apare[node]=0;
        for(int i=0;i<V[node].size();i++)
        {
            int vecin=V[node][i].first;
            int DtillV=V[node][i].second;
            if(D[node]+DtillV<D[vecin])
            {
                D[vecin]=D[node]+DtillV;
                if(apare[vecin]==1)
                {
                    if(noD[vecin]>n)
                    {
                        negativeCycle=1;
                        continue;
                    }
                }else
                {
                    apare[vecin]=1;
                    coada.push(make_pair(D[vecin],vecin));
                    noD[vecin]++;
                }
            }
        }
    }
    if(negativeCycle)
        fo<<"Ciclu negativ!";
    else
    {
        for(int i=2;i<=n;i++)
            fo<<D[i]<<" ";
    }
}
int main()
{
    fi>>n>>m;
    for(int i=1;i<=m;i++)
    {
        int x,y,cost;
        fi>>x>>y>>cost;
        V[x].push_back(make_pair(y,cost));
    }
    for(int i=2;i<=n;i++)
        D[i]=INF;
    D[1]=0;
    int source=1;
    BellmanFordMoore(source);
    return 0;
}