Cod sursa(job #1096339)

Utilizator raulmuresanRaul Muresan raulmuresan Data 1 februarie 2014 21:37:31
Problema Algoritmul Bellman-Ford Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.83 kb
/* Algortimul lui Bellman Ford
Complexitate O(m*n)

*/
#include <cstdio>
#include <algorithm>
#include<vector>
#include<queue>

using namespace std;

int nod,minim,i,aux,n,k,j,p,s,unu,t,m,doi,x,st,dr,maxi,sol,maxi2,viz[50010],y,conex,cost,d[50010],ok;
vector < pair<int, int> > v[50010];
bool negative;
bool inside[50010];//verificam daca un nod este deja introdus in coada
int nr[50010];//nr de cate ori a fost introdus un nod in coada


queue <int> q;
void bellman()
{

    while(! q.empty())
    {
        nod=q.front();
        inside[nod]=false;
        q.pop();
        //printf("%d\n",nod);
        for(i=0;i<v[nod].size();i++)
        {
            if(d[v[nod][i].first] > d[nod]+v[nod][i].second)
            {
                d[v[nod][i].first] = d[nod]+v[nod][i].second;
                if(inside[v[nod][i].first] == false)
                {
                    q.push(v[nod][i].first);
                    inside[v[nod][i].first]=true;
                    nr[v[nod][i].first]++;
                    if(nr[v[nod][i].first]++ > n)
                    {
                        negative=true;
                        return;

                    }

                }

            }
        }
    }

}


int main()
{
    freopen ("bellmanford.in","r",stdin);
    freopen ("bellmanford.out","w",stdout);
    scanf("%d%d",&n,&m);
    for(i=1;i<=m;i++)
    {
        scanf("%d %d %d",&x,&y,&cost);
        v[x].push_back(make_pair(y,cost));
    }
     for(i=2;i<=n;i++)
    {
        d[i]=100000000;
    }
    q.push(1);
    nr[1]++;
    inside[1]=true;


    bellman();
    if(negative ==true)
    {
        printf("Ciclu negativ!");
    }
    else{
    for(i=2;i<=n;i++)
    {
        if(d[i]==100000000)
        printf("0 ");
        else
        printf("%d ",d[i]);
    }
    }
}