Cod sursa(job #3040809)

Utilizator Tudor06MusatTudor Tudor06 Data 30 martie 2023 14:27:14
Problema 2SAT Scor 0
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.91 kb
#include <bits/stdc++.h>

using namespace std;

const int NMAX = 1e5;

vector <int> edges[2 * NMAX];

void add_edges( int a, int b ) {
    edges[a ^ 1].push_back( b );
    edges[b ^ 1].push_back( a );
}

int comp[2 * NMAX], found_time[2 * NMAX], min_found[2 * NMAX];

bool viz[2 * NMAX];
stack <int> st;

int t = 0, cur_comp;

void dfs( int node, int p = -1 ) {
    found_time[node] = min_found[node] = t ++;
    viz[node] = true;
    st.push( node );
    for ( auto vec : edges[node] ) {
        if ( !viz[vec] ) {
            dfs( vec, node );
            min_found[node] = min( min_found[node], min_found[vec] );
            if ( min_found[vec] > found_time[node] ) {
                while ( st.top() != vec ) {
                    comp[st.top()] = cur_comp;
                    st.pop();
                }
                comp[st.top()] = cur_comp;
                st.pop();
                cur_comp ++;
            }
        } else if ( vec != p && found_time[vec] < found_time[node] ) {
            min_found[node] = min( min_found[node], found_time[node] );
        }
    }
}
int main() {
    ifstream fin( "2sat.in" );
    ofstream fout( "2sat.out" );
    int n, m;
    fin >> n >> m;
    for ( int i = 1, a, b; i <= m; i ++ ) {
        fin >> a >> b;
        a = ( a < 0 ) ? -a * 2 - 1 : a * 2 - 2;
        b = ( b < 0 ) ? -b * 2 - 1 : b * 2 - 2;
//        cout << "THE NODES ARE: " << a << ' ' << b << '\n';
        add_edges( a, b );
    }
//    cout << endl;
    dfs( 0 );
    while ( !st.empty() ) {
        comp[st.top()] = cur_comp;
        st.pop();
    }
    bool sepoate = true;
    for ( int i = 0; i < 2 * n; i ++ ) {
        if ( comp[i] == comp[i ^ 1] ) sepoate = false;
    }
    if ( sepoate ) {
        for ( int i = 0; i < 2 * n; i += 2 ) {
            fout << ( comp[i] < comp[i ^ 1] ) << ' ';
        }
    } else {
        fout << -1;
    }
    return 0;
}