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Cod sursa(job #756674)
#include <cstdio>
#include <fstream>
#include <vector>
#include <utility>
#include <algorithm>
#include <queue>
using namespace std;
vector <int> bellman_ford (int sursa, int n, vector <vector < pair <int, int> > > &G, bool &ok) {
vector < pair <int, int> > :: iterator it;
vector <int> len, d;
queue <int> q;
len.resize (n + 1);
d.resize (n + 1, 1 << 30);
ok = true;
d [sursa] = 0;
len [sursa] = 0;
q.push (sursa);
while (ok && !q.empty ()) {
sursa = q.front ();
q.pop ();
for (it = G [sursa].begin (); it != G [sursa].end (); ++ it) {
if (d [it->first] > d [sursa] + it->second) {
d [it->first] = d [sursa] + it->second;
len [it->first] = 1 + len [sursa];
q.push (it->first);
if (len [it->first] >= n) {
ok = false;
break;
}
}
}
}
return d;
}
int main () {
vector <vector < pair <int, int> > > G;
vector <int> d;
bool ok;
int i, n, m, x, y, c;
ifstream f ("bellmanford.in");
ofstream g ("bellmanford.out");
f >> n >> m;
G.resize (n + 1);
for (i = 0; i < m; ++ i) {
f >> x >> y >> c;
G [x].push_back (make_pair (y, c));
}
d = bellman_ford (1, n, G, ok);
if (! ok) {
g << "Ciclu negativ!\n";
}
else {
if (d [2] == (1 << 30)) {
d [2] = 0;
}
g << d [2];
for (i = 3; i <= n; ++ i) {
if (d [i] == (1 << 30)) {
d [i] = 0;
}
g << " " << d [i];
}
g << "\n";
}
return 0;
}