Pagini recente » Cod sursa (job #2132634) | Cod sursa (job #1865942) | Istoria paginii runda/infolimpiada/clasament | Cod sursa (job #993776) | Cod sursa (job #2528906)
#include <bits/stdc++.h>
#define DIM 200010
using namespace std;
ifstream fin("2sat.in");
ofstream fout("2sat.out");
int n,m,x,y,i,ok,nivel,sol[DIM],niv[DIM],low[DIM];
vector<int> L[DIM];
set<int> v;
bitset<DIM> f,instack;
stack<int> st;
void dfs(int nod) {
niv[nod]=low[nod]=++nivel;
st.push(nod);
f[nod]=instack[nod]=1;
for (int i=0;i<L[nod].size();i++) {
int vecin=L[nod][i];
if (!f[vecin]) {
dfs(vecin);
low[nod]=min(low[nod],low[vecin]);
}
else
if (instack[vecin])
low[nod]=min(low[nod],niv[vecin]);
}
if (low[nod]==niv[nod]) {
v.clear();
do {
x=st.top();
st.pop();
instack[x]=0;
if ((x<=n&&v.find(x+n)!=v.end())||(x>n&&v.find(x-n)!=v.end())) //daca am mai intalnit deja valoarea sau negatie ei nu avem solutie
ok=-1;
v.insert(x);
if (sol[x]==0) {
sol[x]=1;
if (x<=n)
sol[x+n]=-1;
else
sol[x-n]=-1;
}
}
while (x!=nod);
}
}
int main() {
fin>>n>>m;
while (m--) {
fin>>x>>y;
if (x>0) {
if (y>0) {
L[x+n].push_back(y);
L[y+n].push_back(x);
}
else {
L[x+n].push_back(-y+n);
L[-y].push_back(x);
}
}
else {
if (y>0) {
L[-x].push_back(y);
L[y+n].push_back(-x+n);
}
else {
L[-x].push_back(-y+n);
L[-y].push_back(-x+n);
}
}
}
for (i=1;i<=2*n;i++)
if (!f[i])
dfs(i);
if (ok==1)
fout<<"-1\n";
else
for (i=1;i<=n;i++) {
if (sol[i]==-1)
fout<<"0 ";
else
fout<<"1 ";
}
return 0;
}