Pagini recente » Cod sursa (job #225136) | Istoria paginii implica-te/arhiva-educationala | Cod sursa (job #369659) | Cod sursa (job #381833)
Cod sursa(job #381833)
#include <stdio.h>
#include <vector>
#include <set>
#include <algorithm>
using namespace std;
#define maxn 50010
#define maxm 250010
#define inf 1000000000
#define pb push_back
#define mp make_pair
struct muchie
{
long a, b, c;
} e[maxm];
long n, m, i, j, k, left, right, cost[maxn], f[maxn];
vector <long> v[maxn];
vector <pair<long, long> > h;
void init()
{
long i;
cost[1]=0;
for(i=2; i<=n; i++)
cost[i]=inf;
h.pb(mp(0, 1));
make_heap(h.begin(), h.end());
}
void solve()
{
pair<long, long> per;
long i, j, nod, poz;
long long pas=0;
while(h.size() && pas<=1LL*n*m)
{
pas++;
pop_heap(h.begin(), h.end());
per=h.back();
h.pop_back();
nod=per.second;
f[nod]=0;
for(j=0; j<v[nod].size(); j++)
{
poz=v[nod][j];
if(cost[e[poz].a]+e[poz].c<cost[e[poz].b])
{
cost[e[poz].b]=cost[e[poz].a]+e[poz].c;
if(!f[e[poz].b])
{
f[e[poz].b]=1;
h.pb(mp(-cost[e[poz].b], e[poz].b));
push_heap(h.begin(), h.end());
}
}
}
}
}
long check_negativ()
{
long i;
for(i=1; i<=m; i++)
if(cost[e[i].a]+e[i].c<cost[e[i].b])
return 1;
return 0;
}
int main()
{
freopen("bellmanford.in", "r", stdin);
freopen("bellmanford.out", "w", stdout);
scanf("%d%d", &n, &m);
for(i=1; i<=m; i++)
{
scanf("%d%d%d", &e[i].a, &e[i].b, &e[i].c);
v[e[i].a].pb(i);
}
init();
solve();
if(check_negativ())
{
printf("Ciclu negativ!\n");
return 0;
}
for(i=2; i<=n; i++)
printf("%d ", cost[i]);
return 0;
}