Cod sursa(job #1969418)

Utilizator TibixbAndrei Tiberiu Tibixb Data 18 aprilie 2017 14:15:41
Problema Algoritmul Bellman-Ford Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.52 kb
#include<fstream>
#include<vector>
#include<queue>
#define NMAX 100005
#define INF 2000000000
using namespace std;
vector<pair<int, int> > G[NMAX];
queue<int> q;
int n, m, x, y, z;
int nod;
int d[NMAX], na[NMAX];
bool u[NMAX];
ifstream _cin("bellmanford.in");
ofstream _cout("bellmanford.out");

bool bellmanford()
{
    q.push(1);
    u[1] = 1;
    na[1] = 1;

    while(!q.empty())
    {
        nod = q.front();
        q.pop();
        u[nod] = 0;

        for(int i = 0; i < G[nod].size(); i++)
        {
            int fiu = G[nod][i].first;
            int dist = G[nod][i].second;
            if(d[fiu] > d[nod] + dist)
            {
                d[fiu] = d[nod] + dist;

                if(u[fiu] == 0)
                {
                    na[fiu]++;
                    if(na[fiu] == n)
                    {
                        _cout << "Ciclu negativ!";
                        return 0;
                    }
                    q.push(fiu);
                    u[fiu] = 1;
                }
            }
        }
    }

    return 1;
}

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

void init()
{
    for(int i = 1 + 1; i <= n; i++)
    {
        d[i] = INF;
    }
}

int main()
{
    _cin >> n >> m;
    for(int i = 1; i <= m; i++)
    {
        _cin >> x >> y >> z;
        G[x].push_back(make_pair(y, z));
    }

    init();

    if(bellmanford())
    {
        afisare();
    }
    return 0;
}