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Cod sursa(job #609984)
#include<stdio.h>
#include<vector.h>
#define pb push_back
#define N 200001
long n,m,i,a[N],b[N],j,p[N],w[N],c[N],nr,r,l,d[N],v[N],k;
vector<long> f[N],g[N];
void dfs(long x)
{long i;
c[x]=1;
for(i=0;i<f[x].size();i++)
if(!c[f[x][i]])
dfs(f[x][i]);
w[++nr]=x;}
void dfst(long x)
{long i;
c[x]=0;
if(p[x]==2)
{p[x]=0;
if(x>n)
p[x-n]=1;
else
p[x+n]=1;}
for(i=0;i<g[x].size();i++)
if(c[g[x][i]])
dfst(g[x][i]);}
void ts(long x)
{long i;
d[x]=1;
for(i=f[x].size()-1;i>=0;i--)
ts(f[x][i]);
v[++k]=x;}
int main()
{freopen("2sat.in","r",stdin);
freopen("2sat.out","w",stdout);
scanf("%ld%ld",&n,&m);
for(i=1;i<=m;i++)
{scanf("%ld%ld",&a[i],&b[i]);
if(a[i]<0)
a[i]=n-a[i];
if(b[i]<0)
b[i]=n-b[i];
if(a[i]>n)
f[a[i]-n].pb(b[i]),g[b[i]].pb(a[i]-n);
else
f[a[i]+n].pb(b[i]),g[b[i]].pb(a[i]+n);
if(b[i]>n)
f[b[i]-n].pb(a[i]),g[a[i]].pb(b[i]-n);
else
f[b[i]+n].pb(a[i]),g[a[i]].pb(b[i]+n);}
for(j=1;j<=2*n;j++)
{p[j]=2;
if(!c[j])
dfs(j);}
r=0;
for(i=nr;i;i--)
if(c[i])
{dfst(w[i]);
r++;}
if(r==1)
{l=0;
for(i=1;i<=2*n;i++)
if(!g[i].size())
{l=i;
break;}
if(l)
ts(l);
for(i=k;i;i--)
if(p[i]==2)
{p[i]=0;
if(i>n)
p[i-n]=1;
else
p[i+n]=1;}}
for(j=1;j<=m;j++)
if(!p[a[j]]&&!p[b[j]])
{printf("-1");
return 0;}
for(i=1;i<=n;i++)
printf("%d ",p[i]);
return 0;}