CS 475 Midterm: CS 475 Alabama Fall2017 Exam2 1
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You may choose any set of problems that adds up to 100 or more points: write all the strings of length 6 that are generated by this context-free grammar. Name ____________________ a parse tree for each such string. [30 points for cs 475] [20 points for cs 575] Y cyf | : write all the strings of lengths 3 and 6 that are accepted by this pushdown automaton. Hint: first get the strings of length 3, then use these to get the strings of length 6. [30 points for cs 475] [20 points for cs 575] a, /t b, /u c, /vw f, v/ g, w/ h, x/ d, /x. , z0/ e, / j, t/ k, / . , u/ : write an unambiguous context-free grammar for the language consisting of all the strings over {a,b} such that the number of a"s is not equal to the number of b"s. Alternatively, write an ambiguous cfg for this language.
