Cod sursa(job #2368826)

Utilizator vladboss2323Ciorica Vlad vladboss2323 Data 5 martie 2019 18:30:51
Problema Algoritmul Bellman-Ford Scor 65
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.41 kb
#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
using namespace std;

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

const int N=25005;
const int oo=100000000;
vector<pair <int,int> > a[N];
queue <int> Q;
int n,m,d[N];
bool viz[N];
int nr[N];

void citire()
{
    int i,x,y,z;
    in>>n>>m;
    for(i=1; i<=m; i++)
    {
        in>>x>>y>>z;
        a[x].push_back(make_pair(y,z));
    }
}

int BellmanFord()
{
    int ok=1,vecin,cost,i;
    for(i=2; i<=n; i++)
        d[i]=oo;
    Q.push(1);
    viz[1]=1;
    nr[1]=1;
    while(!Q.empty() && ok==1)
    {
        int nod=Q.front();
        viz[nod]=0;
        Q.pop();
        for(i=0; i<a[nod].size(); i++)
        {
            cost=a[nod][i].second;
            vecin=a[nod][i].first;
            if(d[vecin]>d[nod]+cost)
            {
                d[vecin]=d[nod]+cost;
                if(viz[vecin]==0)
                {
                    Q.push(vecin);
                    viz[vecin]=1;
                    nr[vecin]++;
                    if(nr[vecin]>n)
                        ok=-1;
                }
            }
        }
    }
    return ok;
}

void afisare()
{
    for(int i=2; i<=n; i++)
        out<<d[i]<<" ";
}


int main()
{

    citire();
    if(BellmanFord()==-1)
        out<<"Ciclu negativ!";
    else
        afisare();
    return 0;
}