Cod sursa(job #1685336)

Utilizator TibixbAndrei Tiberiu Tibixb Data 11 aprilie 2016 16:59:48
Problema Algoritmul Bellman-Ford Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.34 kb
#include<fstream>
#include<vector>
#include<cstring>
#include<queue>
#define inf 0x7f7f7f7f
using namespace std;
vector<pair<int, int> > L[50002];
queue<int> q;
bool u[50002];
int n, m, i, x, y, z, D[50002], ok, nod, vecin, cost, nrap[50002];
void bellmanford()
{
    while(!q.empty())
    {
        nod=q.front();
        for(i=0; i<L[nod].size(); i++)
        {
            vecin=L[nod][i].first;
            cost=L[nod][i].second;
            if(D[vecin]>D[nod]+cost)
            {
                D[vecin]=D[nod]+cost;
                if(u[vecin]==0)
                {
                    q.push(vecin);
                    u[vecin]=1;
                    nrap[vecin]++;
                    if(nrap[vecin]==n)
                    {
                        ok=1;
                        return ;
                    }
                }
            }
        }
        u[nod]=0;
        q.pop();
    }
}
ifstream in("bellmanford.in");
ofstream out("bellmanford.out");
int main()
{
    in>>n>>m;
    for(i=1; i<=m; i++)
    {
        in>>x>>y>>z;
        L[x].push_back(make_pair(y, z));
    }
    memset(D, inf, sizeof(D));
    D[1]=0;
    q.push(1);
    bellmanford();
    if(ok==1)
        out<<"Ciclu negativ!";
    else
    {
        for(i=2; i<=n; i++)
            out<<D[i]<<" ";
    }
    return 0;
}