hws/hw01.tex
changeset 841 564840440523
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    86 
    86 
    87 \item What is meant by the notions \emph{evil regular expressions}
    87 \item What is meant by the notions \emph{evil regular expressions}
    88   and by \emph{catastrophic backtracking}?
    88   and by \emph{catastrophic backtracking}?
    89 
    89 
    90 \item Given the regular expression $(a + b)^* \cdot b \cdot (a + b)^*$,
    90 \item Given the regular expression $(a + b)^* \cdot b \cdot (a + b)^*$,
    91   which of the following regular expressions are equyivalent
    91   which of the following regular expressions are equivalent
    92 
    92 
    93 \begin{center}
    93 \begin{center}
    94 \begin{tabular}{ll}    
    94 \begin{tabular}{ll}    
    95   1) & $(ab + bb)^* \cdot (a + b)^*$\\                     % no
    95   1) & $(ab + bb)^* \cdot (a + b)^*$\\                     % no
    96   2) & $(a + b)^* \cdot (ba + bb + b) \cdot (a + b)^*$\\   % yes
    96   2) & $(a + b)^* \cdot (ba + bb + b) \cdot (a + b)^*$\\   % yes