Question

Give regular expressions generating the languages of

1. {w over the alphabet of {0, 1} | w is any string except 11 and 111}

2. {w over the alphabet of {0, 1} | w contains at least two 0’s and at most one 1}

3. {w over the alphabet of {0, 1} | the length of w is at most 9}

4. {w over the alphabet of {0, 1} | w contains at least three 1 s}

5. {w over the alphabet of {0, 1} | w starts with 0 and has odd length, or starts with 1 and has even length}

Answer 1

O+1