C++ (Cpp) NFA::get_epsilon_transitionsの例

コード例 #1

//==========================================================================================================
// Calculate the epsiolon closure for a state in the NFA. This is needed for constructing the DFA.
//==========================================================================================================
set<int> DFA::calc_epsilon_closure(int state, NFA& nfa) {
    set<int> res;
    vector<int> cur_states;
    res.insert(state);
    cur_states.push_back(state);
    
    //------------------------------------------------------------------------------------------------------
    // As long as there are states in the list, add their epsilon neighbors, but only if they weren't added
    // yet
    //------------------------------------------------------------------------------------------------------
    for(int i = 0; i < cur_states.size(); ++i) {
        for(int s: nfa.get_epsilon_transitions(cur_states[i])) {
            if(res.count(s) == 0) {
                res.insert(s);
                cur_states.push_back(s);
            }
        }
    }
    
    return res;
}