for c in s:

			new_state = set()

			for st in current:

				key = (st, c)

				if key in self.rules:

					new_state.update(self.rules[key])

			current = new_state

		return any(st in self.end_states for st in current)

	def determinize(self):

		alphabet_index = {c: i for (i, c) in enumerate(sorted(self.alphabet))}

		n = len(alphabet_index)

		compact_rules = [-1] * n

		end_states = {0} if -1 in self.end_states else set()

		index = {(-1,): 0}

		stack = [(-1,)]

		while stack:

			multistate = stack.pop()

			new_rules = dict()

			for ((st, c), target) in filter(lambda item: item[0][0] in multistate, self.rules.items()):

				if c not in new_rules:

					new_rules[c] = set()

				new_rules[c].update(target)

			for (c, target_set) in new_rules.items():

				target_tup = tuple(sorted(target_set))

				if target_tup not in index:

					new_target = len(index)

					index[target_tup] = new_target

					compact_rules.extend([-1] * n)

					stack.append(target_tup)

				compact_rules[index[multistate]*n + alphabet_index[c]] = index[target_tup]

				if any(st in self.end_states for st in target_set):

					end_states.add(index[target_tup])

		fail = len(index)

		compact_rules = [(st if st >= 0 else fail) for st in compact_rules]

		compact_rules.extend([fail] * n)

		return (compact_rules, end_states, alphabet_index)

class RegexpDFA:

	def __init__(self, rules, end_states, alphabet_index):

		self.end_states = end_states

	@classmethod

	def create(cls, pattern):

		r = Regexp(pattern)

		(rules, end_states, alphabet_index) = r.determinize()

		return cls(rules, end_states, alphabet_index)

	def match(self, s):

		st = 0

		n = len(self.alphabet_index)

		for c in s:

				return False

			key = (st*n + self.alphabet_index[c])

			st = self.rules[key]

		return st in self.end_states

	def reduce(self):

		equivalents = self._find_equivalent_states()

		(rules, end_states) = self._collapse_states(equivalents)

		return RegexpDFA(rules, end_states, self.alphabet_index)

	def normalize(self):

		n = len(self.alphabet_index)

		index = {0: 0}

		queue = deque([0])

		rules = []

		while queue:

			si = queue.popleft()

			row = self.rules[si*n:(si+1)*n]

			for sj in row:

				if sj not in index:

					index[sj] = len(index)

					queue.append(sj)

			rules.extend(index[sj] for sj in row)

		end_states = {index[si] for si in self.end_states if si in index}

		return RegexpDFA(rules, end_states, self.alphabet_index)

	def find_distinguishing_string(self, r):

		if self.rules == r.rules and self.end_states == r.end_states:

			return None

		r1 = self._expand_alphabet(r.alphabet_index)

		r2 = r._expand_alphabet(self.alphabet_index)

		product = r1._build_product_automaton(r2)

		n = len(product.alphabet_index)

		reverse_alphabet_index = {v: k for (k, v) in product.alphabet_index.items()}

		queue = deque([(0, "")])

		visited = {0}

		while queue:

			(state, acc) = queue.popleft()

			if state in product.end_states:

				return acc

		if r.is_skippable() {

			end_states.insert(START_NFA);

		}

		let mut alphabet_vec = Vec::from_iter(alphabet.into_iter());

		alphabet_vec.sort();

		return Ok(Regexp{rules, end_states, alphabet: alphabet_vec});

	}

	pub fn eval(&self, s: String) -> bool {

		let mut multistate = HashSet::from([START_NFA]);

		for c in s.chars() {

			let mut new_multistate = HashSet::new();

			for state in multistate {

				if let Some(x) = self.rules.get(&(state, c)) {

					new_multistate = new_multistate.union(&x).map(|&y| y).collect();

				} else if let Some(x) = self.rules.get(&(state, '.')) {

					new_multistate = new_multistate.union(&x).map(|&y| y).collect();

				}

			}

			multistate = new_multistate;

		}

		return multistate.iter().any(|x| self.end_states.contains(x));

	}

	pub fn determinize(&self) -> RegexpDFA {

		const FAIL: usize = usize::MAX;

		let alphabet_index: HashMap<char, usize> = self.alphabet.iter().enumerate().map(|(i, c)| (*c, i)).collect();

		let n = alphabet_index.len();

		let mut compact_rules = vec![FAIL; n];

		let mut end_states: HashSet<usize> = HashSet::new();

		if self.end_states.contains(&START_NFA) {end_states.insert(START_DFA);}

		// string hash -> single int DFA state

		let mut index_new = HashMap::from([(START_NFA.to_string(), START_DFA)]);

		// string hash -> HashSet NFA multistate

		let mut index_multi = HashMap::from([(START_NFA.to_string(), HashSet::from([START_NFA]))]);

		let mut stack = Vec::from([START_NFA.to_string()]);

		while !stack.is_empty() {

			let state_hash = stack.pop().unwrap();

			let multistate = &index_multi[&state_hash];

			let mut new_rules: HashMap<char, HashSet<usize>> = HashMap::new();

				let (_st, c) = key;

				if !new_rules.contains_key(c) {

					new_rules.insert(*c, HashSet::new());

				}

				for target in &self.rules[key] {

					new_rules.get_mut(c).unwrap().insert(*target);

				}

			}

			for (c, target_set) in new_rules.into_iter() {

				let target_hash = encode_set(&target_set);

				let is_end = target_set.iter().any(|st| self.end_states.contains(st));

				if !index_new.contains_key(&target_hash) {

					let target_new = index_new.len();

					index_new.insert(target_hash.clone(), target_new);

					index_multi.insert(target_hash.clone(), target_set);

					compact_rules.extend(iter::repeat(FAIL).take(n));

					stack.push(target_hash.clone());

				}

				compact_rules[index_new[&state_hash]*n + alphabet_index[&c]] = index_new[&target_hash];

				if is_end {

					end_states.insert(index_new[&target_hash]);

				}

			}

		}

		let fail = index_new.len();

		compact_rules = compact_rules.into_iter().map(|st| if st != FAIL {st} else {fail}).collect();

		compact_rules.extend(iter::repeat(fail).take(n));

	}

}

#[derive(Clone)]

pub struct RegexpDFA {

	rules: Vec<usize>,

	end_states: HashSet<usize>,

	alphabet_index: HashMap<char, usize>

}

impl RegexpDFA {

	pub fn eval(&self, s: String) -> bool {

		let n = self.alphabet_index.len();

		let mut state = START_DFA;

		for c in s.chars() {

			if let Some(ci) = self.alphabet_index.get(&c) {

				state = self.rules[state*n + ci];

			} else {

				return false;

			}

		}

		return self.end_states.contains(&state);

	}

	pub fn reduce(&self) -> RegexpDFA {

		let equivalents = self.find_equivalent_states();

		return self.collapse_states(equivalents);

	}

	pub fn normalize(&self) -> RegexpDFA {

		let n = self.alphabet_index.len();

		let m = self.rules.len()/n;

		let fail = m;

		let mut index: Vec<usize> = vec![fail;m];

		index[0] = 0;

		let mut queue = VecDeque::from([START_DFA]);

		let mut rules = vec![];

		let mut k = 1;

		while !queue.is_empty() {

			let si = queue.pop_front().unwrap();

			let row = &self.rules[si*n..(si+1)*n];

			for &sj in row {

				if sj != fail && index[sj] == fail {

					index[sj] = k;

					k += 1;

					queue.push_back(sj);

				}

			}

			rules.extend(row.iter().map(|&st| index[st]));

		}

		let end_states = self.end_states.iter().map(|st| index[*st]).collect();

		return RegexpDFA{rules, end_states, alphabet_index: self.alphabet_index.clone()};

	}

	pub fn find_distinguishing_string(&self, other: &RegexpDFA) -> Option<String> {

		if self.rules == other.rules && self.end_states == other.end_states {

			return None;

		}

		let r1 = self.expand_alphabet(&other.alphabet_index);

		let r2 = other.expand_alphabet(&self.alphabet_index);

		let product = r1.build_product_automaton(&r2);

		let n = product.alphabet_index.len();

		let reverse_alphabet_index: HashMap<usize, char> = HashMap::from_iter(product.alphabet_index.iter().map(|(&k, &v)| (v, k)));

		let mut queue = VecDeque::from([(0, "".to_string())]);

		let mut visited = HashSet::new();

		while !queue.is_empty() {

			let (state, acc) = queue.pop_front().unwrap();

			if product.end_states.contains(&state) {

				return Some(acc);

			}

			for (i, target) in product.rules[state*n..(state+1)*n].iter().enumerate() {

				if !visited.contains(target) {

					queue.push_back((*target, acc.clone()+&String::from(reverse_alphabet_index[&i])));