Cod sursa(job #2575559)

Utilizator mihai03Mihai Grigore mihai03 Data 6 martie 2020 14:21:29
Problema Algoritmul Bellman-Ford Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.52 kb
#include <fstream>
#include <vector>
#include <queue>
#define inf 0x3f3f3f3f
using namespace std;
ifstream fin("bellmanford.in");
ofstream fout("bellmanford.out");
const int nmax = 50005;
int n, m;
vector < pair < int , int > > G[nmax];

int d[nmax];
bool inQueue[nmax];
queue < int > q;

int viz[nmax];

bool BellmanFord(int startNode)
{
    for(int i = 1; i <= n; i++)
        d[i] = inf;
    d[startNode] = 0;
    q.push(startNode);
    inQueue[startNode] = 1;
    while(!q.empty())
    {
        int nodCurent = q.front();
        q.pop();
        inQueue[nodCurent] = false;
        viz[nodCurent]++;
        if(viz[nodCurent] >= n)
            return false;
        for(int i = 0; i < G[nodCurent].size(); i++)
        {
            int vecin = G[nodCurent][i].first;
            int cost = G[nodCurent][i].second;
            if(d[nodCurent] + cost < d[vecin])
            {
                d[vecin] = d[nodCurent] + cost;
                if(!inQueue[vecin])
                {
                    inQueue[vecin] = 1;
                    q.push(vecin);
                }
            }
        }
    }
    return true;
}
int main()
{
    fin >> n >> m;
    for(int i = 1; i <= m; i++)
    {
        int a, b, c;
        fin >> a >> b >> c;
        G[a].push_back(make_pair(b, c));
    }
    if(!BellmanFord(1))
    {
        fout << "Ciclu negativ!";
    }
    else
    {
        for(int i = 2; i <= n; i++)
        {
            fout << d[i] << " ";
        }
    }
    return 0;
}