/* Get next valid char from >= index idx. Return -1 if none or out of bounds */
    void get_next(string& s, int& idx){
        START:
        if ((idx >= s.size()) || (idx < 0)){
            idx = -1; return;
        }

        int b_count = 0;
        while((idx >= 0) && (s[idx] == '#')){
            b_count++; idx--;
        }

        while((idx >= 0) && (b_count > 0)){
            b_count += (s[idx--] == '#') ? 1 : -1;
        }

        /* Might have another set of #, so run again */
        if ((idx >= 0) && (s[idx] == '#')){
            goto START;
        }
    }

    bool backspaceCompare(string S, string T) {
        int s_ptr = S.size()-1;
        int t_ptr = T.size()-1;

        while (1){
            get_next(S, s_ptr); get_next(T, t_ptr);

            if ((s_ptr < 0) && (t_ptr < 0))
                return true;
            if ((s_ptr < 0) || (t_ptr < 0))
                return false;
            if (S[s_ptr--] != T[t_ptr--])
                return false;
        }
    }