GATE_1995

THEORY OF COMPUTATION

HINTS AND SOLUTIONS TO PROBLEMS

Q1.10 ANSWER-------(C)

The last rule has two symbols on the left hand side and the right hand sides of all the rules is as lone as or longer than the left hand side.

Q2.20 ANSWER-------------(A)

The language is a standard cfl which is generated by the productions in I. II gives a regular set and the given language is not regular.

Q2.24ANSWER---------------(C)

L U R is the same as the set of all strings over {0,1} and hence is regular. R is a standard cfl that is not regular.

Q11. For every n there is exactly one string in L. There are only a finite number of strings of length n. Create so many copies of the turing machine and run them one for each string of length n. One of the copies will terminate in polynomial time then terminate the others which accept strings in the complement of L. So we can decide if a string is in L or not in a polynomial amount of time so the complement of L is also in NP.

ANS
1987	1988	1989
1990	1991	1992
1993	1994	1995
1997	1998	1999
2000	2001	2002
2003	2004	1987
QUES
1987	1988	1989
1990	1991	1992
1993	1994	1995
1997	1998	1999
2000	2001	2002
2003	2004	1987

Go to:

2005, GATE THEORY OF COMPUTATION