Cod sursa(job #2282484)

Utilizator mihailrazMihail Turcan mihailraz Data 13 noiembrie 2018 20:05:32
Problema Algoritmul Bellman-Ford Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.33 kb
#include <fstream>
#include <vector>
#include <queue>
#define NMAX 50000
#define INF 2000000000

using namespace std;
ifstream fi("bellmanford.in");
ofstream fo("bellmanford.out");
int n, m;
int DST[NMAX+5], updated[NMAX+5];
vector <pair <int, int> > G[NMAX+5];
queue <int> Q;

void citire(void)
{
    int x, y, c;
    fi>>n>>m;
    for(int i=1; i<=m; i++)
    {
        fi>>x>>y>>c;
        G[x].push_back({c, y});
    }
}

void bellmanFord(void)
{
    int nod, nods, cost;
    for(int i=1; i<=n; i++)
        DST[i]=INF;
    DST[1]=0;
    Q.push(1);
    while(!Q.empty())
    {
        nod=Q.front();
        Q.pop();
        for(auto vec:G[nod])
        {
            nods=vec.second;
            cost=vec.first;
            if(DST[nods]>DST[nod]+cost)
            {
                DST[nods]=DST[nod]+cost;
                updated[nods]++;
                Q.push(nods);
                if(updated[nods]>n-1)
                    return;
            }
        }
    }
}

void afisare(void)
{
    for(int i=1; i<=n; i++)
        if(updated[i]>n-1)
        {
            fo<<"Ciclu negativ!";
            return;
        }
    for(int i=2; i<=n; i++)
        fo<<DST[i]<<" ";
}

int main()
{
    citire();
    bellmanFord();
    afisare();
    fi.close();
    fo.close();
    return 0;
}