Cod sursa(job #1919833)

Utilizator BenosuCusniriuc Beniamin Benosu Data 9 martie 2017 21:13:30
Problema Algoritmul Bellman-Ford Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.45 kb
#include <iostream>
#include <fstream>
#include <queue>
#include <vector>

#define inf 2000000010
#define N 500010

using namespace std;

ifstream f("bellmanford.in");
ofstream g("bellmanford.out");

vector < pair < int,int > > vec[N];
queue <int> que;

bool Q[N],cycle=false;
int i,j,n,m,k,t,dist[N],frecv[N],to,cost;

int main()
{
    int x,y,z;
    f>>n>>m;
    while(m!=0)
    {
        f>>x>>y>>z;
        vec[x].push_back(make_pair(y,z));
        m--;
    }
    for(i=1;i<=n;i++)
        dist[i]=inf;
    Q[1]=0;
    dist[1]=0;
    que.push(1);
    int nod;
    while(!que.empty() && cycle == false )
    {
        nod=que.front();
        Q[nod]=0;
        que.pop();
        vector < pair < int,int > > ::iterator it;
        for(it=vec[nod].begin();it!=vec[nod].end();it++)
        {
            to=it->first;
            cost=it->second;
            if(dist[to]>dist[nod]+cost)
            {
                dist[to]=dist[nod]+cost;
                if(Q[to]==0)
                {
                    if(frecv[to]>n)
                        cycle=true;
                    else
                    {
                        que.push(to);
                        Q[to]=1;
                        frecv[to]++;
                    }
                }
            }
        }
    }
    if(cycle==true)
        g<<"Ciclu negativ!";
    else
    {
        for(i=2;i<=n;i++)
            g<<dist[i]<<' ';
    }
}