Artifact 7827709f822d3c66beb5c1f97e2894b2439e9dd4
// TODO : optimize to O(n log n)
// current version looks to be running in O(n^2) ... orz
//
// TODO : clean up as a library
//
// Copy&Paste from SRM562 Div1 Hard
// Input is given as:
// v----c---->G[v][c]
// Must be a complete automaton.
// !!! The following code is assuming |c|==4 !!!
//
// !!! The following code is assuming the final state is {0}.
//
mint solve(vector< vector<int> >& G)
{
vector< vector<int> > set_buffer;
set<int> active_sets;
set<int> active_splitters;
{
set_buffer.push_back( vector<int>(1,0) );
vector<int> all;
for(int v=1; v<G.size(); ++v)
all.push_back(v);
set_buffer.push_back(all);
active_sets.insert(0);
active_sets.insert(1);
active_splitters.insert(0);
}
while(!active_splitters.empty())
{
const vector<int>& splv = set_buffer[*active_splitters.begin()];
set<int> spl(splv.begin(), splv.end());
active_splitters.erase(active_splitters.begin());
for(int d=0; d<4; ++d)
for(set<int>::iterator it=active_sets.begin(); it!=active_sets.end(); )
{
int ii = *it++;
const vector<int>& cur = set_buffer[ii];
vector<int> t, f;
for(int k=0; k<cur.size(); ++k)
(spl.count(G[cur[k]][d]) ? t : f).push_back(cur[k]);
if(!t.empty() && !f.empty())
{
set_buffer.push_back(t);
set_buffer.push_back(f);
active_sets.insert(set_buffer.size()-2);
active_sets.insert(set_buffer.size()-1);
if(active_splitters.count(ii)) {
active_splitters.insert(set_buffer.size()-2);
active_splitters.insert(set_buffer.size()-1);
} else {
active_splitters.insert(t.size()<f.size() ? set_buffer.size()-2 : set_buffer.size()-1);
}
active_splitters.erase(ii);
active_sets.erase(ii);
}
}
}
vector<int> es;
for(set<int>::iterator it=active_sets.begin(); it!=active_sets.end(); ++it)
if(*it)
es.push_back(set_buffer[*it].size());
/*
for(bool changed=true; changed;)
{
changed=false;
for(int i=0; i<eqs.size(); ++i) if(!eqs[i].second && !dead[i]){
set<int> spl(eqs[i].first.begin(), eqs[i].first.end());
eqs[i].second = true;
for(int k=0; k<eqs.size(); ++k)
for(int d=0; d<4; ++d) if(!dead[k]) {
vector<int> t, f;
for(vector<int>::iterator it=eqs[k].first.begin(); it!=eqs[k].first.end(); ++it)
(spl.count(G[*it][d]) ? t : f).push_back(*it);
if(!t.empty() && !f.empty()) {
if(eqs[k].second) {
eqs.push_back(make_pair(t,t.size()>f.size()));
eqs.push_back(make_pair(f,t.size()<=f.size()));
dead.push_back(false);
dead.push_back(false);
changed = true;
} else {
eqs.push_back(make_pair(t,false));
eqs.push_back(make_pair(f,false));
dead.push_back(false);
dead.push_back(false);
changed = true;
}
dead[k] = true;
}
}
}
}
vector<int> es;
for(int i=1; i<eqs.size(); ++i) if(!dead[i])
es.push_back(eqs[i].first.size());
*/
int sum = accumulate(es.begin(), es.end(), 0);
mint x = POW(2, sum);
for(int i=0; i<es.size(); ++i)
x -= POW(2, es[i])-1;
return x-1;
}