Cod sursa(job #1454529)

Utilizator starduststardust stardust Data 26 iunie 2015 19:16:36
Problema Algoritmul Bellman-Ford Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.48 kb
#include <fstream>
#include <cstdlib>
#include <vector>
#include <queue>
#include <bitset>
#define inf 1<<30
#define maxn 50010

using namespace std;

bitset<maxn> inqueue;
queue<int> q;
int cnt[maxn];

vector<pair<int, int> > a[maxn];

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

int n, m;
int d[maxn];

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

void bellman()
{
    d[1] = 0;
    q.push(1);
    inqueue[1] = true;

    while (!q.empty())
    {
        int nod = q.front();
        q.pop();
        inqueue[nod] = false;

        for (int i = 0; i < a[nod].size(); i++)
        {
            int nodc = a[nod][i].first;
            if (d[nodc] > d[nod] + a[nod][i].second)
            {
                d[nodc] = d[nod] + a[nod][i].second;
                if (inqueue[nodc] == false)
                {
                    inqueue[nodc] = true;
                    q.push(nodc);
                    cnt[nodc]++;
                    if (cnt[nodc] > n)
                    {
                        out << "Ciclu negativ!";
                        exit(0);
                    }
                }
            }
        }
    }
}

int main()
{
    read();
    for (int i = 1; i <= n; i++)
        d[i] = inf;

    bellman();

    for (int i = 2; i <= n; i++)
        if (d[i] == inf)
            out << "0 ";
        else
            out << d[i] << " ";

    return 0;
}