Cod sursa(job #863100)

Utilizator DianaEllenaDiana Elena DianaEllena Data 23 ianuarie 2013 13:38:48
Problema Algoritmul Bellman-Ford Scor 65
Compilator cpp Status done
Runda Arhiva educationala Marime 2.62 kb
#include <fstream>
#include <vector>
#define Infinit 100000000
using namespace std;
ifstream fin("bellmanford.in");
ofstream fout("bellmanford.out");
int n,m,start,val,ok;
int viz[50001],cmin[50001],tata[50001];
int coada[250001],nrpus[50001];

vector<int>c[50001];
vector<int>a[50001];

void citire();
void init();
int bellman_ford(int vf);
void detdrum(int k);
void afisare();

int main()
{
    citire();
    init();
    bellman_ford(1);
    afisare();
    fout.close();
    return 0;
}

void citire()
{
    int i,x,y,cost,j;
    fin>>n>>m;
    for(i=1;i<=m;i++)
    {
        fin>>x>>y>>cost;
        a[x].push_back(y);
        c[x].push_back(cost);
    }
}

void init()
{
     int i;
     for(i=1;i<=n;i++)
        cmin[i]=Infinit;
}

int bellman_ford(int vf)
{
   int i,j,k,inc=1,sf=1,x;
   cmin[vf]=0; coada[1]=vf;
   while(inc<=sf)
   {
       x=coada[inc++];
       for(i=0;i<a[x].size();i++)
       {
            if(cmin[a[x][i]]>cmin[x]+c[x][i])
                {
                    coada[++sf]=a[x][i];
                    cmin[a[x][i]]=cmin[x]+c[x][i];
                    nrpus[a[x][i]]++;
                }
            if(nrpus[a[x][i]]>=n) {ok=1; break;}
       }
       if(ok) break;
   }
   return ok;
}

void afisare()
{
    int i;
    if(ok==1) fout<<"Ciclu negativ!";
    else
        for(i=2;i<=n;i++) fout<<cmin[i]<<' '; //detdrum(i);
}

/*
#include<fstream>
#include<vector>
#define NMAX 50010
#define INF 1000000000

using namespace std;

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

int n;
int cmin[NMAX], coada[500000], nrpus[NMAX];

vector<int>a[NMAX];
vector<int>cost[NMAX];

void citire();
void bell();

int main()
{
    citire();
    bell();
    fout<<'\n';
    fout.close();
    return 0;
}

void citire()
{
    int m, x, y, costv, i;
    fin>>n>>m;
    for(i=1;i<=m;i++)
    {
        fin>>x>>y>>costv;
        cost[x].push_back(costv);
        a[x].push_back(y);
    }
    for(i=1;i<=n;i++)
        cmin[i]=INF;
    cmin[1]=0;
}

void bell()
{
    int inc, sf, i, x, y;
    inc=sf=1; coada[1]=1;
    while(inc<=sf)
    {
        x=coada[inc++];
        for(y=0;y<a[x].size();y++)
            if(cmin[x]+cost[x][y]<cmin[a[x][y]])
            {
                cmin[a[x][y]]=cmin[x]+cost[x][y];
                coada[++sf]=a[x][y];
                nrpus[a[x][y]]++;
                if(nrpus[a[x][y]]>=n)
                {
                    fout<<"Ciclu negativ!";
                    return;
                }
            }
    }
    for(i=2;i<=n;i++)
        fout<<cmin[i]<<' ';
}*/