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Cod sursa(job #419226)
#include <iostream>
#include <fstream>
#include<vector>
#include<queue>
#include<algorithm>
#include<bitset>
using namespace std;
const int MAX_N = 50005;
const int INF = 0x3f3f3f3f;
vector <pair <int, int> > adj[MAX_N];
bitset <MAX_N> in_queue(false);
vector <int> dist(MAX_N, INF), cnt_in_queue(MAX_N, 0);
queue <int> Q;
int main()
{
ifstream in("bellmanford.in");
ofstream out("bellmanford.out");
int nodes, edges;
in >>nodes >>edges;
for (int i = 0; i < edges; ++ i)
{
int x, y, c;
in >>x>>y>>c;
adj[x].push_back(make_pair(y, c));
}
int negative_cycle = false;
dist[1] = 0, Q.push(1), in_queue[1].flip();
while (!Q.empty() && !negative_cycle)
{
int x = Q.front();
Q.pop();
in_queue[x] = false;
vector < pair <int, int> >::iterator it;
for (it = adj[x].begin(); it != adj[x].end(); ++ it) if (dist[x] < INF)
if (dist[it->first] > dist[x] + it->second)
{
dist[it->first] = dist[x] + it->second;
if (!in_queue[it->first])
{
if (cnt_in_queue[it->first] > nodes) negative_cycle = true;
else
{
Q.push(it->first);
in_queue[it->first] = true;
cnt_in_queue[it->first] ++;
}
}
}
}
if (!negative_cycle) for (int i = 2; i <= nodes; ++ i) out << dist[i] << " ";
else out << "Ciclu negativ!\n";
return 0;
}