Cod sursa(job #1450274)

Utilizator greenadexIulia Harasim greenadex Data 12 iunie 2015 12:19:37
Problema Algoritmul Bellman-Ford Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.34 kb
#include <fstream>
#include <iostream>
#include <cstdlib>
#include <deque>
#include <vector>

using namespace std;

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

const int MAX = 50001, inf = (1 << 30) - 1;
deque<int> q;
vector<pair<int, int>> v[MAX];
int m, n, a, b, c, vizq[MAX], viz[MAX], d[MAX];

void bellmanford(int source) {
    for (int i = 1; i <= n; i++)
        d[i] = inf;
    d[source] = 0;
    vizq[source] = 1;
    viz[source] = 1;
    q.push_back(source);
    while (!q.empty()) {
        int node = q.front();
        q.pop_front();
        for (auto it : v[node]) {
            if (it.second + d[node] < d[it.first]) {
                d[it.first] = it.second + d[node];
                if(!vizq[it.first]) {
                    q.push_back(it.first);
                    viz[it.first]++;
                    if (viz[it.first] >= n) {
                        fout << "Ciclu negativ!";
                        exit(0);
                    }
                    vizq[it.first] = 1;
                }
            }
        }
        vizq[node] = 0;
    }
}

int main() {
    fin >> n >> m;
    for (; m; m--) {
        fin >> a >> b >> c;
        v[a].push_back(make_pair(b, c));
    }
    bellmanford(1);
    for (int i = 2; i <= n; i++)
        fout << d[i] << ' ';
    return 0;
}