Cod sursa(job #1344765)

Utilizator SagunistuStrimbu Alexandru Sagunistu Data 16 februarie 2015 22:59:34
Problema Algoritmul Bellman-Ford Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.55 kb
#include <fstream>
#define inf 0x3f3f3f3f
#include <vector>
#include <queue>
#include <cstring>
#include <vector>
#define nmax 50003
#define cost first
#define vecin second

using namespace std;

vector<pair<int,int> >g[nmax];
queue<pair<int,int> >q;
int n,m,nrit[nmax],d[nmax],viz[nmax],ciclu;

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

void citire()
{
    int x,y,c;
    fin>>n>>m;
    for(int i=1;i<=m;i++)
    {
        fin>>x>>y>>c;
        g[x].push_back(make_pair(c,y));
    }
    memset(d,inf,sizeof(d));
}

void rezolv()
{
    int k;
    d[1]=0;
    q.push(make_pair(0,1));
    viz[1]=1;
    while(!q.empty()&&!ciclu)
    {
        k=q.front().second;
        q.pop();
        viz[k]=0;
        vector<pair<int,int> >::iterator ii;
        for(ii=g[k].begin();ii!=g[k].end();++ii)
            if(d[ii->vecin]>ii->cost+d[k])
            {
                d[ii->vecin]=ii->cost+d[k];
                if(viz[ii->vecin]==0)
                {
                    if(nrit[ii->vecin]>n)
                    {
                        ciclu=1;
                        break;
                    }
                    q.push(make_pair(d[ii->vecin],ii->vecin));
                    viz[ii->vecin]=1;
                    nrit[ii->vecin]++;
                }
            }
    }
}

void afisare()
{
    if(ciclu==1)
        fout<<"Ciclu negativ!";
    else
        for(int i=2;i<=n;i++)
            fout<<d[i]<<" ";
}

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