CS150 HW4
       	                Set May 9, Thursday
                        Due May 24, Friday, at 5pm
                        Total: 70 pts


Q1 [10 pts] Construct a CFG for the set of all ternary strings of 
            the form 0^i 1^j 2^k, where k = i + j.

Q2 [10 pts] P. 193 (or P. 191 in 2nd ed)  Ex.5.2.1. That is:
   For the grammar and each of the strings in Ex. 5.1.2, give parse trees.

Q3 [20 pts] P. 216 (or P. 215 in 2nd ed)  Ex.5.4.7.
   The following grammar generates ...

   Hint: For part b, show that the leftmost derivation is unique
   for any given input string, similar to the example given in
   the lecture notes (after slide 169 or page 177).

Q4 [10 pts] PP. 233-4 (or P. 228 in 2nd ed)  Ex.6.1.1: b), c)

Q5 [20 pts] P. 241 (or P. 236 in 2nd ed)  Ex.6.2.1: b), c)

   For each PDA, please show the transition diagram instead of a list
   of transitions.