Cod sursa(job #750080)

Utilizator SpiriFlaviuBerbecariu Flaviu SpiriFlaviu Data 20 mai 2012 15:30:50
Problema Algoritmul Bellman-Ford Scor 10
Compilator cpp Status done
Runda Arhiva educationala Marime 1.55 kb
#include <fstream>
#include <vector>
#include <queue>
#include <bitset>
#define INF 1000000000

using namespace std;

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

vector< pair<int,int> > v[50001];
queue<int> q;
bitset<50001> used;

int c[50001];

int main()
{
    int n,m,x,y,dc;
    fin>>n>>m;
    for(int i=1;i<=m;i++)
    {
        fin>>x>>y>>dc;
        v[x].push_back(make_pair(y,dc));
    }
    for(int i=1;i<=n;i++)
        c[i]=INF;
    int curent = 1;
    c[1]=0;
    q.push(1);
    used[1]=1;
    while(!q.empty())
    {
        curent = q.front();
        used[curent]=1;
        for(int j=0;j<v[curent].size();j++)
        {
            if(c[curent]!=INF)
                if(v[curent][j].second + c[curent] < c[v[curent][j].first])
                {
                    c[v[curent][j].first]=v[curent][j].second + c[curent];
                    if(!used[v[curent][j].first])
                    {
                        //used[curent]=1;
                        q.push(v[curent][j].first);
                    }
                }
        }
        q.pop();
    }


    for(int i=1;i<=n;i++)
        for(int j=0;j<v[i].size();j++)
            if(c[v[i][j].first]!=INF && c[v[i][j].first] > c[i]+v[i][j].second)
            {
                fout<<"Ciclu negativ!\n";
                return 0;
            }

    for(int i=2;i<=n;i++)
        if(c[i]==INF)
            fout<<0<<' ';
        else fout<<c[i]<<' ';
    fout<<'\n';
    fin.close();
    fout.close();
    return 0;
}