Cod sursa(job #2121501)

Utilizator al.mocanuAlexandru Mocanu al.mocanu Data 3 februarie 2018 19:28:06
Problema Algoritmul Bellman-Ford Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.09 kb
#include <fstream>
#include <vector>
#include <queue>
#define pii pair<int, int>
#define mk make_pair
#define f first
#define s second
#define MAX 100005
#define INF 1<<30
using namespace std;

int n, m, d[MAX], t[MAX], x, y, z;
vector<pii> l[MAX];
queue<int> q;

bool bf() {
    for(int i = 2; i <= n; ++i)
        d[i] = INF;

    q.push(1);
    while(!q.empty()) {
        int x = q.front();
        q.pop();

        for(int i = 0; i < l[x].size(); ++i) {
            if(t[l[x][i].f] == n)
                return 0;
            if(d[l[x][i].f] > d[x] + l[x][i].s) {
                d[l[x][i].f] = d[x] + l[x][i].s;
                ++t[l[x][i].f];
                q.push(l[x][i].f);
            }
        }
    }

    return 1;
}

int main() {
    ifstream f("bellmanford.in");
    ofstream g("bellmanford.out");

    f >> n >> m;
    for(int i = 0; i < m; ++i) {
        f >> x >> y >> z;
        l[x].push_back(mk(y, z));
    }

    if(bf()) {
        for(int i = 2; i <= n; ++i)
            g << (d[i] == INF ? 0 : d[i]) << " ";
        g << "\n";
    }
    else
        g << "Ciclu negativ!\n";

    return 0;
}