Cod sursa(job #886012)

Utilizator anca1243Popescu Anca anca1243 Data 22 februarie 2013 16:47:47
Problema Algoritmul Bellman-Ford Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.27 kb
#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
using namespace std;
ifstream in("bellmanford.in");
ofstream out("bellmanford.out");
const int N=50001;
struct cost
{
    int vf,c;
};
vector <cost> a[N];
queue <int> q;
int n,m,d[N],nrq[N];
bool inq[N];
void citire()
{
    int x,y,c;
    cost aux;
    in>>n>>m;
    for(int i=1;i<=m;i++)
    {
        in>>x>>y>>c;
        aux.vf = y;
        aux.c=c;
        a[x].push_back(aux);
    }
}
bool bfs(int x)
{
    int y;
    q.push(x);
    while(!q.empty())
    {
        x=q.front();
        q.pop();
        inq[x]=false;
        for(size_t i=0;i<a[x].size();i++)
        {
            y=a[x][i].vf;
            if(d[y]>d[x]+a[x][i].c)
            {
                d[y]=d[x]+a[x][i].c;
                if(!inq[y])
                {
                    q.push(y);
                    inq[y]=true;
                    nrq[y]++;
                }
            }
        }
        if(nrq[x]==n)
            return false;
    }
    return true;
}
int main()
{
    for(int i=0;i<=N;i++)
        d[i]=10000;
    citire();
    d[1]=0;
    if(bfs(1))
        for(int i=2;i<=n;i++)
            out<<d[i]<<' ';
    else
        out<<"Ciclu negativ!";
    return 0;
}