DFA DFA::FROM_NFA(NFA nfa){
DFA dfa;
NFATable nfa_table = nfa.getTable();
fa_table nfa_table_map = nfa_table.getMapping();
unordered_set<string> visited;
int_set first_set = nfa_table_map[0][Symbol::EPSILON];
queue<int_set> set_queue= queue<int_set>{{first_set}};
// set_queue.push(first_set);
int dfa_state_count = 0;
string set_name = Utils::TO_STRING(first_set);
unordered_map<string, int> dfa_state_mapping
= unordered_map<string, int> {{ set_name, 0 }};
dfa.addState("q" + to_string(0));
int nfa_state_count = nfa_table_map.size();
while (!set_queue.empty()){
int_set curr_state_set = set_queue.front();
set_queue.pop();
// set_name = Utils::TO_STRING(curr_state_set);
string state_name = Utils::TO_STRING(curr_state_set);
if (visited.find(state_name) != visited.end())
continue;
visited.insert(state_name);
bool is_final_state = false;
{
bool states_visited[nfa_state_count] = { 0 };
for (auto st : curr_state_set)
states_visited[st] = true;
for (auto curr_state : curr_state_set){
int_set e_closure = nfa_table_map[curr_state][Symbol::EPSILON];
for (auto e_closure_state : e_closure){
if (!states_visited[e_closure_state]){
curr_state_set.insert(e_closure_state);
states_visited[e_closure_state] = true;
}
}
}
// delete states_visited;
}
for (auto symbol : nfa_table.getAlphabet()){
if (symbol == Symbol::EPSILON)
continue;
int_set next_set;
bool states_visited[nfa_state_count] = { 0 };
for (auto curr_state : curr_state_set){
if (!is_final_state && curr_state == nfa_table.getFinalState())
is_final_state = true;
if (nfa_table_map[curr_state].find(symbol) != nfa_table_map[curr_state].end()){
int_set next_states = nfa_table_map[curr_state][symbol];
for (auto ns : next_states){
int_set e_closure = nfa_table_map[ns][Symbol::EPSILON];
for (auto e_closure_state : e_closure){
if (!states_visited[e_closure_state]){
next_set.insert(e_closure_state);
states_visited[e_closure_state] = true;
}
}
}
}
}
string next_state_name = Utils::TO_STRING(next_set);
if (next_set.size() > 0){
if (dfa_state_mapping.find(next_state_name) == dfa_state_mapping.end()){
// dfa.addState(next_state_name);
dfa_state_count++;
dfa.addState("q" + to_string(dfa_state_count));
dfa_state_mapping.insert({next_state_name, dfa_state_count});
}
dfa.addTransition(dfa_state_mapping[state_name], dfa_state_mapping[next_state_name], symbol);
}
// else{
// dfa.addTransition(dfa_state_mapping[state_name], 0, symbol);
// }
if (is_final_state)
dfa.addFinalState(dfa_state_mapping[state_name]);
if (next_set.size() > 0 && visited.find(next_state_name) == visited.end()){
set_queue.push(next_set);
}
// delete states_visited;
}
}
return dfa;
}
