Cod sursa(job #1201002)

Utilizator tdr_drtTdr Drt tdr_drt Data 24 iunie 2014 11:45:23
Problema Algoritmul Bellman-Ford Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.42 kb
#include<fstream>
#include<vector>
#include<queue>
#include<cstdio>
using namespace std;
vector<pair<int,int> > lista[50001];
queue<int>q;
bool ok[50001];
int n,m,relaxari[50001],dist[50001];

void read()
{
    ifstream f("bellmanford.in");
    int x,y,w;
    f>>n>>m;
    for(int i=1;i<=m;i++)
    {
        f>>x>>y>>w;
        lista[x].push_back(make_pair(y,w));
    }
    f.close();
}

void write(bool cond)
{
    ofstream g("bellmanford.out");
    if(cond==0)
    {
        g<<"Ciclu negativ!";
    }
    else
    {
        for(int i=2;i<=n;i++)
        g<<dist[i]<<" ";
    }
    g.close();
}

int bellmanford()
{
    int i,y,w;

    for(i=2;i<=n;i++)
    {
        dist[i]=9999999;
    }
    dist[1]=0;
    q.push(1);

    while(!q.empty())
    {
        i=q.front();
        q.pop();
        relaxari[i]++;
        if(relaxari[i]==n)
        {
            write(0);
            return 0;
        }
        ok[i]=0;
        for(int j=0;j<lista[i].size();j++)
        {
            y=lista[i][j].first;
            w=lista[i][j].second;
            if(dist[i]+w<dist[y])
            {
                dist[y]=dist[i]+w;
                if(ok[y]==0)
                {
                    ok[y]=1;
                    q.push(y);
                }
            }
        }
    }
    write(1);
   return 0;
}

int main()
{
    read();
    bellmanford();

    return 0;
}