Pagini recente » Cod sursa (job #1530977) | Cod sursa (job #1208609) | Cod sursa (job #1906571) | Cod sursa (job #3279628) | Cod sursa (job #2886517)
#include <bits/stdc++.h>
#define INF 0x3f3f3f3f
using namespace std;
ifstream fin("2sat.in");
ofstream fout("2sat.out");
const int kN = 2e5;
vector<int> g[1 + kN];
int n, m, timer, vf, N, tin[1 + kN], low[1 + kN], stk[1 + kN], ctcIndex[1 + kN];
void minSelf(int &x, int y) {
if (y < x) {
x = y;
}
}
int neg(int i) {
if (i <= n) {
return i + n;
}
return i - n;
}
void addEdge(int i, int j) {
g[i].emplace_back(j);
}
void addOr(int i, int j) {
addEdge(neg(i), j);
addEdge(neg(j), i);
}
int getNode(int x) {
if (x < 0) {
return n - x;
}
return x;
}
void dfs(int u) {
tin[u] = ++timer;
low[u] = timer;
stk[++vf] = u;
for (int v : g[u]) {
if (tin[v]) {
minSelf(low[u], tin[v]);
} else {
dfs(v);
minSelf(low[u], low[v]);
}
}
if (tin[u] == low[u]) {
int node;
do {
node = stk[vf];
tin[node] = INF;
ctcIndex[node] = N;
vf -= 1;
} while (node != u);
N += 1;
}
}
void testCase() {
fin >> n >> m;
for (int i = 0; i < m; ++i) {
int x, y;
fin >> x >> y;
addOr(getNode(x), getNode(y));
}
for (int i = 1; i <= 2 * n; ++i) {
if (!tin[i]) {
dfs(i);
}
}
for (int i = 1; i <= n; ++i) {
if (ctcIndex[i] == ctcIndex[i + n]) {
fout << "-1\n";
return;
}
}
for (int i = 1; i <= n; ++i) {
if (ctcIndex[i] < ctcIndex[i + n]) {
fout << "1 ";
} else {
fout << "0 ";
}
}
}
int main() {
int tests = 1;
for (int tc = 0; tc < tests; ++tc) {
testCase();
}
fin.close();
fout.close();
return 0;
}