equal
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inserted
replaced
54 \item Let $A = \{[a], [b], [c], [d]\}$. (1) How many strings |
54 \item Let $A = \{[a], [b], [c], [d]\}$. (1) How many strings |
55 are in $A^4$? (2) Consider also the case of $A^4$ where one of |
55 are in $A^4$? (2) Consider also the case of $A^4$ where one of |
56 the strings in $A$ is the empty string, for example $A = |
56 the strings in $A$ is the empty string, for example $A = |
57 \{[a], [b], [c], []\}$. |
57 \{[a], [b], [c], []\}$. |
58 |
58 |
59 \item (1)How many basic regular expressions are there to match |
59 \item (1) How many basic regular expressions are there to match |
60 the string $abcd$? (2) How many if they cannot include |
60 the string $abcd$? (2) How many if they cannot include |
61 $\ONE$ and $\ZERO$? (3) How many if they are also not |
61 $\ONE$ and $\ZERO$? (3) How many if they are also not |
62 allowed to contain stars? (4) How many if they are also |
62 allowed to contain stars? (4) How many if they are also |
63 not allowed to contain $\_ + \_$? |
63 not allowed to contain $\_ + \_$? |
64 |
64 |