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Cod sursa(job #744027)
#include <cstdio>
#include <vector>
using namespace std;
const int kMaxN = 200005;
vector <int> L[kMaxN], LT[kMaxN];
int N, ft[kMaxN], sol[kMaxN];
inline int non(int x) {
return (x <= n) ? (x + n) : (x - n);
}
void read() {
int M, a, b;
assert(scanf("%d%d", &N, &M) == 2);
for (int i = 1; i <= M; ++ i) {
assert(scanf("%d%d", &a, &b) == 2);
if (a < 0)
a = n + (- a);
if (b < 0)
b = n + (- b);
L[non(a)].push_back(b);
L[non(b)].push_back(a);
LT[b].push_back(non(a));
LT[a].push_back(non(b));
}
}
bool impossible, viz[kMaxN];
void make_vec(int nod) {
viz[nod] = 1;
for (int i = 0; i < L[nod].size(); ++ i)
if (! viz[L[nod][i]])
make_vec(L[nod][i]);
ft[++ ft[0]] = nod;
}
void ctc(int nod) {
if (sol[nod])
impossible = 1;
viz[nod] = 1;
sol[non(nod)] = 1;
for (int i = 0; i < LT[nod].size(); ++ i)
if (! viz[LT[nod][i]])
ctc(LT[nod][i]);
}
void reset() {
for (int i = 1; i <= 2 * n; ++ i)
viz[i] = 0;
}
void solve() {
for (int i = 1; i <= 2 * n; ++ i)
if (! viz[i])
make_vec(i);
reset();
for (int i = 2 * n; i >= 1; -- i)
if ((! viz[ft[i]]) && (! viz[non(ft[i])]))
ctc(ft[i]);
if (impossible) {
printf("-1\n");
return;
}
for (int i = 1; i <= n; ++ i)
printf("%d ", sol[i]);
}
int main() {
freopen("2sat.in", "r", stdin);
freopen("2sat.out", "w", stdout);
read();
solve();
return 0;
}