Cod sursa(job #3154916)

Utilizator hhhhhhhAndrei Boaca hhhhhhh Data 6 octombrie 2023 20:04:45
Problema 2SAT Scor 40
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 2.28 kb
#include <bits/stdc++.h>

using namespace std;
ifstream fin("2sat.in");
ofstream fout("2sat.out");
typedef pair<int,int> pii;
int n,m,use[600005],comp[600005],sol[600005];
vector<int> muchii[600005];
vector<int> nodes[600005];
int nr;
vector<pii> g;
vector<int> st;
int grad[600005];
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)
{
    comp[nod]=nr;
    nodes[nr].push_back(nod);
    for(int i:muchii[nod])
        if(comp[i]==0)
            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);
        muchii[-b+n].push_back(a+n);
        g.push_back({-a+n,b+n});
        g.push_back({-b+n,a+n});
    }
    for(int i=1;i<=n;i++)
        if(!use[i])
            dfs1(i);
    reverse(st.begin(),st.end());
    for(int i=1;i<=n;i++)
    {
        muchii[-i+n].clear();
        muchii[i+n].clear();
        sol[-i+n]=-1;
        sol[i+n]=-1;
    }
    for(auto i:g)
        muchii[i.second].push_back(i.first);
    for(int i:st)
        if(comp[i]==0)
        {
            nr++;
            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<=nr;i++)
        muchii[i].clear();
    for(auto i:g)
    {
        int a=comp[i.first];
        int b=comp[i.second];
        if(a!=b)
        {
            muchii[a].push_back(b);
            grad[b]++;
        }
    }
    queue<int> coada;
    for(int i=1;i<=nr;i++)
        if(grad[i]==0)
            coada.push(i);
    while(!coada.empty())
    {
        int c=coada.front();
        coada.pop();
        int x=nodes[c][0];
        if(sol[x]==-1)
        {
            for(int j:nodes[c])
            {
                int nod=j-n;
                sol[j]=0;
                sol[-nod+n]=1;
            }
        }
        for(int i:muchii[c])
        {
            grad[i]--;
            if(grad[i]==0)
                coada.push(i);
        }
    }
    for(int i=1;i<=n;i++)
        fout<<sol[i+n]<<' ';
    return 0;
}