solution.cpp

class Solution
{
public:
    bool parseBoolExpr(string expression)
    {
        stack<char> st;

        for (char c : expression)
        {
            if (c == ')')
            {
                vector<char> subExpr;
                while (st.top() != '(')
                {
                    subExpr.push_back(st.top());
                    st.pop();
                }
                st.pop(); // Remove '('

                char op = st.top();
                st.pop(); // Remove the operator

                if (op == '!')
                {
                    st.push(subExpr[0] == 't' ? 'f' : 't');
                }
                else if (op == '&')
                {
                    char result = 't';
                    for (char e : subExpr)
                    {
                        if (e == 'f')
                        {
                            result = 'f';
                            break;
                        }
                    }
                    st.push(result);
                }
                else if (op == '|')
                {
                    char result = 'f';
                    for (char e : subExpr)
                    {
                        if (e == 't')
                        {
                            result = 't';
                            break;
                        }
                    }
                    st.push(result);
                }
            }
            else if (c != ',')
            {
                st.push(c);
            }
        }

        return st.top() == 't';
    }
};