Cod sursa(job #1675557)

Utilizator GinguIonutGinguIonut GinguIonut Data 5 aprilie 2016 13:23:13
Problema Algoritmul Bellman-Ford Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.44 kb
#include <fstream>
#include <vector>
#include <string.h>
#include <queue>

#define nMax 50001
#define INF (1 << 30)
#define pb push_back
#define mkp make_pair

using namespace std;
ifstream fin("bellmanford.in");
ofstream fout("bellmanford.out");
int n, m;
int dist[nMax], viz[nMax], frecv[nMax];
vector<pair<int, int> > G[nMax];
queue<int> Q;
void read()
{
    int a, b, c;
    fin>>n>>m;

    for(int i=1;i<=m;i++)
    {
        fin>>a>>b>>c;
        G[a].pb(mkp(b, c));
    }
}
void write()
{
    for(int i=2;i<=n;i++)
        fout<<dist[i]<<" ";
}
void solve()
{
    int S=1;

    for(int i=2;i<=n;i++)
        dist[i]=INF;

    for(Q.push(S);!Q.empty();)
    {
        int node=Q.front();
        viz[node]=0;
        Q.pop();

        for(vector<pair<int, int> >::iterator it=G[node].begin();it!=G[node].end();it++)
        {
            int fiu=it->first;
            int dst=it->second;

            if(dist[node]+dst<dist[fiu])
            {
                dist[fiu]=dist[node]+dst;
                frecv[fiu]++;

                if(frecv[fiu]>=n)
                {
                    fout<<"Ciclu negativ!";
                    return;
                }

                if(viz[fiu]==0)
                {
                    viz[fiu]=1;
                    Q.push(fiu);
                }

            }
        }
    }
    write();
}
int main()
{
    read();
    solve();
    return 0;
}