Cod sursa(job #1610528)

Utilizator SagunistuStrimbu Alexandru Sagunistu Data 23 februarie 2016 17:00:57
Problema Algoritmul Bellman-Ford Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.49 kb
#include <cstdio>
#include <vector>
#include <queue>
#include <cstring>
#define inf 0x3f3f3f3f
#define nmax 50005
#define vecin second
#define cost first

using namespace std;

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

void citire()
{
    int x,y,c;
    scanf("%d%d",&n,&m);
    for(int i=1;i<=m;i++)
    {
        scanf("%d%d%d",&x,&y,&c);
        g[x].push_back(make_pair(c,y));
    }
}

void bellman_ford()
{
    int k;
    memset(d,inf,sizeof(d));
    q.push(make_pair(0,1));
    viz[1]=1;
    d[1]=0;
    while(!q.empty())
    {
        k=q.front().vecin;
        q.pop();
        viz[k]=0;
        if(nrit[k]>n)
        {
            ok=1;
            break;
        }
        for(vector<pair<int,int> >::iterator 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)
                {
                    q.push(make_pair(d[ii->vecin],ii->vecin));
                    viz[ii->vecin]=1;
                    nrit[ii->vecin]++;
                }
            }
    }
}

void afisare()
{
    if(ok)
        printf("Ciclu negativ!");
    else
        for(int i=2;i<=n;i++)
            printf("%d ",d[i]);
}

int main()
{
    freopen("bellmanford.in","r",stdin);
    freopen("bellmanford.out","w",stdout);
    citire();
    bellman_ford();
    afisare();
    return 0;
}