Cod sursa(job #3208106)

Utilizator hhhhhhhAndrei Boaca hhhhhhh Data 27 februarie 2024 19:24:23
Problema 2SAT Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.88 kb
#include <bits/stdc++.h>

using namespace std;
ifstream fin("2sat.in");
ofstream fout("2sat.out");
typedef pair<int,int> pii;
bool use[200005];
int n,m,comp[200005],sol[200005];
vector<int> st;
vector<int> muchii[200005];
vector<pii> g;
int nrcomp;
vector<int> who[200005];
void dfs1(int nod)
{
    use[nod]=1;
    for(int i:muchii[nod])
        if(!use[i])
            dfs1(i);
    st.push_back(nod);
}
void dfs2(int nod)
{
    who[nrcomp].push_back(nod);
    comp[nod]=nrcomp;
    for(int i:muchii[nod])
        if(!comp[i])
            dfs2(i);
}
int main()
{
    ios_base::sync_with_stdio(false);
    fin.tie(0);
    fin>>n>>m;
    for(int i=1;i<=m;i++)
    {
        int a,b;
        fin>>a>>b;
        muchii[-a+n].push_back(b+n);
        g.push_back({-a+n,b+n});
        muchii[-b+n].push_back(a+n);
        g.push_back({-b+n,a+n});
    }
    for(int i=1;i<=n;i++)
    {
        if(!use[i+n])
            dfs1(i+n);
        if(!use[-i+n])
            dfs1(-i+n);
    }
    reverse(st.begin(),st.end());
    for(int i=0;i<=2*n;i++)
    {
        use[i]=0;
        muchii[i].clear();
    }
    for(auto i:g)
        muchii[i.second].push_back(i.first);
    for(int i:st)
        if(!comp[i])
        {
            nrcomp++;
            dfs2(i);
        }
    for(int i=1;i<=n;i++)
        if(comp[i+n]==comp[-i+n])
        {
            fout<<-1;
            return 0;
        }
    for(int i=1;i<=nrcomp;i++)
    {
        bool go=1;
        for(int j:who[i])
            if(use[j])
                go=0;
        if(!go)
            continue;
        for(int j:who[i])
        {
            int x=j-n;
            if(x>0)
                sol[x]=0;
            else
                sol[abs(x)]=1;
            use[j]=1;
            use[-x+n]=1;
        }
    }
    for(int i=1;i<=n;i++)
        fout<<sol[i]<<' ';
    return 0;
}