Cod sursa(job #2071188)

Utilizator darisavuSavu Daria darisavu Data 20 noiembrie 2017 14:23:11
Problema Algoritmul Bellman-Ford Scor 15
Compilator cpp Status done
Runda Arhiva educationala Marime 1.3 kb
#include <fstream>
#include <cstdlib>
#define inf 100000000
using namespace std;
ifstream f("bellmanford.in");
ofstream g("bellmanford.out");
int n,m,c[1005][1005],d[250005],use[250005];
void citire()
{
    int i,j,x,y,cost;
    f>>n>>m;
    for(i=1;i<=n;i++)
        for(j=1;j<=n;j++)
    {
        if(j==i) c[i][j]=0;
        else c[i][j]=inf;
    }
    for(i=1;i<=m;i++)
    {
        f>>x>>y>>cost;
        c[x][y]=cost;
    }
}
void dijkstra(int s)
{
    int i,k,mn,x,j;
    for(i=1;i<=n;i++) d[i]=inf;
    d[s]=0;
    for(k=1;k<=n;k++)
    { mn=inf;
        for(i=1;i<=n;i++)
             if(!use[i]&&d[i]<mn)
            {
                mn=d[i];
                x=i;
            }
            if(mn==inf) break;
            use[x]=1;
            for(j=1;j<=n;j++)
            {
                if(d[x]+c[x][j]<d[j])
                {
                    d[j]=d[x]+c[x][j];
                }
            }
    }
    for(i=1;i<=n;i++)
        for(j=1;j<=n;j++)
    {
        if(c[j][i]==inf&&j!=i&&d[j]+c[j][i]<d[i])
        {
            g<<"Ciclu negativ!";
            exit(0);
        }
    }
}
int main()
{
    citire();
    dijkstra(1);
    for(int i=2;i<=n;i++)
    {
        if(d[i]==inf) g<<0<<" ";
        else g<<d[i]<<" ";

    }
    return 0;
}