Pagini recente » Cod sursa (job #690591) | Cod sursa (job #326072) | Cod sursa (job #614268) | Cod sursa (job #2003299) | Cod sursa (job #3040809)
#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;
}