Cod sursa(job #1419848)

Utilizator Liviu98Dinca Liviu Liviu98 Data 16 aprilie 2015 21:51:40
Problema Algoritmul Bellman-Ford Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.4 kb
#include <iostream>
#include <stdio.h>
#include <fstream>
#include <vector>
#include <cstring>
#include <deque>
#define NMax 50010
using namespace std;
const long INFINIT=1000000000;
vector< pair < int,int > > Graf[NMax];
deque <int> Q;
long N,M,x,y,z,D[NMax],C[NMax];
bool Ciclu=false;

void Read()
{
    freopen("bellmanford.in", "r", stdin);
    scanf("%d%d",&N,&M);
    for(int i=1;i<=M;i++)
    {
        scanf("%d%d%d",&x,&y,&z);
        Graf[x].push_back(make_pair(y,z));
    }
}

void BellmanFord(const int &nodstart)
{
    Q.push_back(nodstart);
    for(int i=0;i<=N;i++)
        D[i]=INFINIT;
    D[1]=0;
    while(!Q.empty())
    {
        int nod=Q.front();
        Q.pop_front();
        for(int i=0;i<Graf[nod].size() && Ciclu==false;i++)
        {
            if(D[Graf[nod][i].first]>D[nod]+Graf[nod][i].second)
            {
                D[Graf[nod][i].first]=D[nod]+Graf[nod][i].second;
                Q.push_back(Graf[nod][i].first);
                C[Graf[nod][i].first]++;
                if(C[Graf[nod][i].first]>N)
                    Ciclu=true;
            }
        }
    }
}

void Write()
{
    freopen("bellmanford.out", "w", stdout);
    BellmanFord(1);
    if(Ciclu==false)
    {
        for(int i=2;i<=N;i++)
            printf("%d ",D[i]);
    }
    else
        printf("Ciclu negativ!");
}

int main()
{
    Read();
    Write();
}