Machine-translated by Google. Questions are authored in English.
Top

GATE CS 2012: Computer Science and Information Technology

  • Paper code: CS
  • Language: English
  • 19 pages
GATE CS 2012 question paper, GATE 2012, Computer Science and Information Technology, page 1 of 19
Page 1 of 19
Text of page 1
2012                                                                       Question Booklet Code
         CS : COMPUTER SCIENCE & INFORMATION TECHNOLOGY                                                    A
Duration: Three Hours                                                                    Maximum Marks: 100

Read the following instructions carefully.

    1. Do not open the seal of the Question Booklet until you are asked to do so by the invigilator.
    2. Take out the Optical Response Sheet (ORS) from this Question Booklet without breaking the seal
       and read the instructions printed on the ORS carefully. If you find that the Question Booklet Code
       printed at the right hand top corner of this page does not match with the Booklet Code on the ORS,
       exchange the booklet immediately with a new sealed Question Booklet.
    3. On the right half of the ORS, using ONLY a black ink ball point pen, (i) darken the bubble
       corresponding to your test paper code and the appropriate bubble under each digit of your registration
       number and (ii) write your registration number, your name and name of the examination centre and
       put your signature at the specified location.
    4. This Question Booklet contains 20 pages including blank pages for rough work. After you are
       permitted to open the seal, please check all pages and report discrepancies, if any, to the invigilator.
    5. There are a total of 65 questions carrying 100 marks. All these questions are of objective type. Each
       question has only one correct answer. Questions must be answered on the left hand side of the ORS
       by darkening the appropriate bubble (marked A, B, C, D) using ONLY a black ink ball point pen
       against the question number. For each question darken the bubble of the correct answer. More
       than one answer bubbled against a question will be treated as an incorrect response.
    6. Since bubbles darkened by the black ink ball point pen cannot be erased, candidates should darken
       the bubbles in the ORS very carefully.
    7. Questions Q.1 – Q.25 carry 1 mark each. Questions Q.26 – Q.55 carry 2 marks each. The 2 marks
       questions include two pairs of common data questions and two pairs of linked answer questions. The
       answer to the second question of the linked answer questions depends on the answer to the first
       question of the pair. If the first question in the linked pair is wrongly answered or is unattempted, then
       the answer to the second question in the pair will not be evaluated.
    8. Questions Q.56 – Q.65 belong to General Aptitude (GA) section and carry a total of 15 marks.
       Questions Q.56 – Q.60 carry 1 mark each, and questions Q.61 – Q.65 carry 2 marks each.

    9. Unattempted questions will result in zero mark and wrong answers will result in NEGATIVE marks.
       For all 1 mark questions, ⅓ mark will be deducted for each wrong answer. For all 2 marks questions,
       ⅔ mark will be deducted for each wrong answer. However, in the case of the linked answer question
       pair, there will be negative marks only for wrong answer to the first question and no negative marks
       for wrong answer to the second question.
    10. Calculator is allowed whereas charts, graph sheets or tables are NOT allowed in the examination hall.
    11. Rough work can be done on the question paper itself. Blank pages are provided at the end of the
        question paper for rough work.
    12. Before the start of the examination, write your name and registration number in the space provided
        below using a black ink ball point pen.

              Name

              Registration Number            CS

CS-A                                                                                                         1/20
GATE CS 2012 question paper, GATE 2012, Computer Science and Information Technology, page 2 of 19
Page 2 of 19
Text of page 2
2012                                                                     COMPUTER SCIENCE & INFORMATION TECH. – CS
Q. 1 – Q. 25 carry one mark each.
 Q.1   Consider the following logical inferences.

       I1: If it rains then the cricket match will not be played.
           The cricket match was played.
           Inference: There was no rain.
       I2: If it rains then the cricket match will not be played.
           It did not rain.
           Inference: The cricket match was played.

       Which of the following is TRUE?
       (A) Both I1 and I2 are correct inferences
       (B) I1 is correct but I2 is not a correct inference
       (C) I1 is not correct but I2 is a correct inference
       (D) Both I1 and I2 are not correct inferences

 Q.2   Which of the following is TRUE?
       (A) Every relation in 3NF is also in BCNF
       (B) A relation R is in 3NF if every non-prime attribute of R is fully functionally dependent on every
           key of R
       (C) Every relation in BCNF is also in 3NF
       (D) No relation can be in both BCNF and 3NF

 Q.3   What will be the output of the following C program segment?

       char inChar = ‘A’ ;
       switch ( inChar ) {
       case ‘A’ : printf (“Choice A\ n”) ;
       case ‘B’ :
       case ‘C’ : printf (“Choice B”) ;
       case ‘D’ :
       case ‘E’ :
       default : printf ( “ No Choice” ) ; }
       (A) No Choice
       (B) Choice A
       (C) Choice A
            Choice B No Choice
       (D) Program gives no output as it is erroneous
 Q.4   Assuming P ≠ NP, which of the following is TRUE?
       (A) NP-complete = NP                                  (B) NP-complete ∩ P = 
       (C) NP-hard = NP                                      (D) P = NP-complete

 Q.5   The worst case running time to search for an element in a balanced binary search tree with n2n
       elements is
       (A) Θ (n log n)           (B) Θ (n2n)                 (C) Θ (n)                (D) Θ (log n)




CS-A                                                                                                           2/20
GATE CS 2012 question paper, GATE 2012, Computer Science and Information Technology, page 3 of 19
Page 3 of 19
Text of page 3
2012                                                                COMPUTER SCIENCE & INFORMATION TECH. – CS
 Q.6    The truth table
                                                  X    Y     f (X, Y)
                                                  0    0         0
                                                  0    1         0
                                                  1    0         1
                                                  1    1         1
        represents the Boolean function
        (A) X                   (B) X + Y                  (C) X  Y              (D) Y

 Q.7    The decimal value 0.5 in IEEE single precision floating point representation has
        (A) fraction bits of 000…000 and exponent value of 0
        (B) fraction bits of 000…000 and exponent value of −1
        (C) fraction bits of 100…000 and exponent value of 0
        (D) no exact representation

 Q.8    A process executes the code
                fork();
                fork();
                fork();
        The total number of child processes created is
        (A) 3                   (B) 4                      (C) 7                  (D) 8

 Q.9    Consider the function f(x) = sin(x) in the interval x  [π/4, 7π/4]. The number and location(s) of the
        local minima of this function are
        (A) One, at π/2
        (B) One, at 3π/2
        (C) Two, at π/2 and 3π/2
        (D) Two, at π/4 and 3π/2

 Q.10   The protocol data unit (PDU) for the application layer in the Internet stack is
        (A) Segment             (B) Datagram               (C) Message            (D) Frame

 Q.11   Let A be the 2 × 2 matrix with elements a11 = a12 = a21 = +1 and a22 = −1. Then the eigenvalues of
        the matrix A19 are
        (A) 1024 and −1024                                 (B) 1024√2 and −1024√2
        (C) 4√2 and −4√2                                   (D) 512√2 and −512√2

 Q.12   What is the complement of the language accepted by the NFA shown below?
        Assume  = {a} and  is the empty string.



                                   a                           



                                                 
        (A)                    (B) {}                    (C) a*                 (D) {a , }

CS-A                                                                                                        3/20
GATE CS 2012 question paper, GATE 2012, Computer Science and Information Technology, page 4 of 19
Page 4 of 19
Text of page 4
2012                                                               COMPUTER SCIENCE & INFORMATION TECH. – CS
 Q.13   What is the correct translation of the following statement into mathematical logic?
                                           “Some real numbers are rational”
        (A) x (real(x)  rational(x))
        (B) x (real(x)  rational(x))
        (C) x (real(x)  rational(x))
        (D) x (rational(x)  real(x))

 Q.14   Given the basic ER and relational models, which of the following is INCORRECT?
        (A) An attribute of an entity can have more than one value
        (B) An attribute of an entity can be composite
        (C) In a row of a relational table, an attribute can have more than one value
        (D) In a row of a relational table, an attribute can have exactly one value or a NULL value

 Q.15   Which of the following statements are TRUE about an SQL query?

        P : An SQL query can contain a HAVING clause even if it does not have a GROUP BY clause
        Q : An SQL query can contain a HAVING clause only if it has a GROUP BY clause
        R : All attributes used in the GROUP BY clause must appear in the SELECT clause
        S : Not all attributes used in the GROUP BY clause need to appear in the SELECT clause
        (A) P and R             (B) P and S              (C) Q and R             (D) Q and S

 Q.16   The recurrence relation capturing the optimal execution time of the Towers of Hanoi problem with
        n discs is
        (A) T(n) = 2T(n − 2) + 2                         (B) T(n) = 2T(n − 1) + n
        (C) T(n) = 2T(n/2) + 1                           (D) T(n) = 2T(n − 1) + 1

 Q.17   Let G be a simple undirected planar graph on 10 vertices with 15 edges. If G is a connected graph,
        then the number of bounded faces in any embedding of G on the plane is equal to
        (A) 3                   (B) 4                    (C) 5                   (D) 6
 Q.18   Let W(n) and A(n) denote respectively, the worst case and average case running time of an
        algorithm executed on an input of size n. Which of the following is ALWAYS TRUE?
        (A) A(n) = Ω (W(n))                              (B) A(n) = Θ (W(n))
        (C) A(n) = O (W(n))                              (D) A(n) = o (W(n))

 Q.19   The amount of ROM needed to implement a 4 bit multiplier is
        (A) 64 bits             (B) 128 bits             (C) 1 Kbits             (D) 2 Kbits

 Q.20   Register renaming is done in pipelined processors
        (A) as an alternative to register allocation at compile time
        (B) for efficient access to function parameters and local variables
        (C) to handle certain kinds of hazards
        (D) as part of address translation

 Q.21   Consider a random variable X that takes values +1 and −1 with probability 0.5 each. The values of
        the cumulative distribution function F(x) at x = −1 and +1 are
        (A) 0 and 0.5           (B) 0 and 1              (C) 0.5 and 1           (D) 0.25 and 0.75


CS-A                                                                                                     4/20
GATE CS 2012 question paper, GATE 2012, Computer Science and Information Technology, page 5 of 19
Page 5 of 19
Text of page 5
2012                                                                COMPUTER SCIENCE & INFORMATION TECH. – CS
 Q.22   Which of the following transport layer protocols is used to support electronic mail?
        (A) SMTP                (B) IP                   (C) TCP                  (D) UDP

 Q.23   In the IPv4 addressing format, the number of networks allowed under Class C addresses is
        (A) 214                 (B) 27                   (C) 221                  (D) 224

 Q.24   Which of the following problems are decidable?

                    1)   Does a given program ever produce an output?
                    2)   If L is a context-free language, then, is L also context-free?
                    3)   If L is a regular language, then, is L also regular?
                    4)   If L is a recursive language, then, is L also recursive?
        (A) 1, 2, 3, 4          (B) 1, 2                 (C) 2, 3, 4              (D) 3, 4

 Q.25   Given the language L = {ab, aa, baa}, which of the following strings are in L*?

                    1)   abaabaaabaa
                    2)   aaaabaaaa
                    3)   baaaaabaaaab
                    4)   baaaaabaa
        (A) 1, 2 and 3                                   (B) 2, 3 and 4
        (C) 1, 2 and 4                                   (D) 1, 3 and 4




CS-A                                                                                                      5/20
GATE CS 2012 question paper, GATE 2012, Computer Science and Information Technology, page 6 of 19
Page 6 of 19
Text of page 6
2012                                                               COMPUTER SCIENCE & INFORMATION TECH. – CS

Q. 26 to Q. 55 carry two marks each.
 Q.26   Which of the following graphs is isomorphic to




        (A)                                              (B)




        (C)                                              (D)




 Q.27   Consider the following transactions with data items P and Q initialized to zero:
        T1 :read (P);
            read (Q);
            if P = 0 then Q := Q + 1 ;
            write (Q).
        T2 : read (Q);
            read (P);
            if Q = 0 then P := P + 1 ;
            write (P).
        Any non-serial interleaving of T1 and T2 for concurrent execution leads to
        (A) a serializable schedule
        (B) a schedule that is not conflict serializable
        (C) a conflict serializable schedule
        (D) a schedule for which a precedence graph cannot be drawn
 Q.28   The bisection method is applied to compute a zero of the function f(x) = x4 – x3 – x2 – 4 in the
        interval [1,9]. The method converges to a solution after ––––– iterations.
        (A) 1                    (B) 3                    (C) 5                   (D) 7
 Q.29   Let G be a weighted graph with edge weights greater than one and G be the graph constructed by
        squaring the weights of edges in G. Let T and T be the minimum spanning trees of G and G,
        respectively, with total weights t and t. Which of the following statements is TRUE?
        (A) T = T with total weight t = t2
        (B) T = T with total weight t < t2
        (C) T ≠ T but total weight t = t2
        (D) None of the above
CS-A                                                                                                       6/20
GATE CS 2012 question paper, GATE 2012, Computer Science and Information Technology, page 7 of 19
Page 7 of 19
Text of page 7
2012                                                                   COMPUTER SCIENCE & INFORMATION TECH. – CS
 Q.30   What is the minimal form of the Karnaugh map shown below? Assume that X denotes a don’t care
        term.
                         ab
                      cd      00     01     11    10

                        00      1      X         X       1

                        01      X                        1

                        11

                        10      1                       X


        (A) b d                 (B) b d  b c                (C) b d  ab c d       (D) b d  b c  c d
 Q.31   Consider the 3 processes, P1, P2 and P3 shown in the table.

                                       Process       Arrival       Time Units
                                                     time          Required
                                       P1            0             5
                                       P2            1             7
                                       P3            3             4

        The completion order of the 3 processes under the policies FCFS and RR2 (round robin scheduling
        with CPU quantum of 2 time units) are
        (A) FCFS: P1, P2, P3 RR2: P1, P2, P3                 (B) FCFS: P1, P3, P2 RR2: P1, P3, P2
        (C) FCFS: P1, P2, P3 RR2: P1, P3, P2                 (D) FCFS: P1, P3, P2 RR2: P1, P2, P3
 Q.32   Fetch_And_Add(X,i) is an atomic Read-Modify-Write instruction that reads the value of
        memory location X, increments it by the value i, and returns the old value of X. It is used in the
        pseudocode shown below to implement a busy-wait lock. L is an unsigned integer shared variable
        initialized to 0. The value of 0 corresponds to lock being available, while any non-zero value
        corresponds to the lock being not available.

            AcquireLock(L){
                  while (Fetch_And_Add(L,1))
                        L = 1;
            }

            ReleaseLock(L){
                  L = 0;
            }

        This implementation
        (A) fails as L can overflow
        (B) fails as L can take on a non-zero value when the lock is actually available
        (C) works correctly but may starve some processes
        (D) works correctly without starvation
 Q.33   Suppose a fair six-sided die is rolled once. If the value on the die is 1, 2, or 3, the die is rolled a
        second time. What is the probability that the sum total of values that turn up is at least 6?
        (A) 10/21               (B) 5/12                     (C) 2/3                (D) 1/6
CS-A                                                                                                         7/20
GATE CS 2012 question paper, GATE 2012, Computer Science and Information Technology, page 8 of 19
Page 8 of 19
Text of page 8
2012                                                              COMPUTER SCIENCE & INFORMATION TECH. – CS
 Q.34   An Internet Service Provider (ISP) has the following chunk of CIDR-based IP addresses available
        with it: 245.248.128.0/20. The ISP wants to give half of this chunk of addresses to Organization A,
        and a quarter to Organization B, while retaining the remaining with itself. Which of the following is
        a valid allocation of addresses to A and B?
        (A) 245.248.136.0/21 and 245.248.128.0/22
        (B) 245.248.128.0/21 and 245.248.128.0/22
        (C) 245.248.132.0/22 and 245.248.132.0/21
        (D) 245.248.136.0/24 and 245.248.132.0/21

 Q.35   Suppose a circular queue of capacity (n −1) elements is implemented with an array of n elements.
        Assume that the insertion and deletion operations are carried out using REAR and FRONT as array
        index variables, respectively. Initially, REAR = FRONT = 0. The conditions to detect queue full
        and queue empty are
        (A) full: (REAR+1) mod n == FRONT               (B) full: (REAR+1) mod n == FRONT
            empty: REAR == FRONT                            empty: (FRONT+1) mod n == REAR

        (C) full: REAR == FRONT                         (D) full: (FRONT+1) mod n == REAR
            empty: (REAR+1) mod n == FRONT                 empty: REAR == FRONT




CS-A                                                                                                       8/20
GATE CS 2012 question paper, GATE 2012, Computer Science and Information Technology, page 9 of 19
Page 9 of 19
Text of page 9
2012                                                                COMPUTER SCIENCE & INFORMATION TECH. – CS
 Q.36   Consider the program given below, in a block-structured pseudo-language with lexical scoping and
        nesting of procedures permitted.
        Program main;
           Var ...

              Procedure A1;
                 Var ...
                 Call A2;
              End A1

              Procedure A2;
                 Var ...

                  Procedure A21;
                     Var ...
                     Call A1;
                  End A21

                 Call A21;
              End A2

           Call A1;
        End main.

        Consider the calling chain: Main  A1  A2  A21  A1

        The correct set of activation records along with their access links is given by
        (A)                                              (B)

                           Main                                              Main

                            A1                                                A1

                            A2                                                A2

                           A21                                               A21

                            A1                                                A1
              FRAME                    ACCESS                  FRAME                      ACCESS
              POINTER                  LINKS                   POINTER                    LINKS




        (C)                                              (D)

                           Main                                              Main

              FRAME         A1                                                A1
              POINTER
                            A2                                                A2

                           A21                                               A21
                                       ACCESS
                                       LINKS                                  A1
                                                               FRAME                      ACCESS
                                                               POINTER                    LINKS



CS-A                                                                                                      9/20
GATE CS 2012 question paper, GATE 2012, Computer Science and Information Technology, page 10 of 19
Page 10 of 19
Text of page 10
2012                                                                            COMPUTER SCIENCE & INFORMATION TECH. – CS
 Q.37   How many onto (or surjective) functions are there from an n-element (n  2) set to a 2-element set?
        (A) 2n                   (B) 2n − 1            (C) 2n − 2                (D) 2(2n – 2)
 Q.38   Let G be a complete undirected graph on 6 vertices. If vertices of G are labeled, then the number of
        distinct cycles of length 4 in G is equal to
        (A) 15                 (B) 30                   (C) 90              (D) 360
 Q.39   A list of n strings, each of length n, is sorted into lexicographic order using the merge-sort
        algorithm. The worst case running time of this computation is
        (A) O (n log n)         (B) O (n2 log n)         (C) O (n2 + log n)     (D) O (n2)
 Q.40   Consider the directed graph shown in the figure below. There are multiple shortest paths between
        vertices S and T. Which one will be reported by Dijkstra’s shortest path algorithm? Assume that, in
        any iteration, the shortest path to a vertex v is updated only when a strictly shorter path to v is
        discovered.
                                                                 2
                                                     E
                                 C           1       D       2
                                                                        G
                         1
                     A                           1
                                         3
                                                                 4
                 4                                                          3
                                 7                           3
             S                                       D
                                             4
                             3                       5
                                                                 5                 T
                     3

                                     B                   F




        (A) SDT                  (B) SBDT                (C) SACDT              (D) SACET
 Q.41   A file system with 300 GByte disk uses a file descriptor with 8 direct block addresses, 1 indirect
        block address and 1 doubly indirect block address. The size of each disk block is 128 Bytes and the
        size of each disk block address is 8 Bytes. The maximum possible file size in this file system is
        (A) 3 KBytes
        (B) 35 KBytes
        (C) 280 KBytes
        (D) dependent on the size of the disk
 Q.42   Consider the virtual page reference string
             1, 2, 3, 2, 4, 1, 3, 2, 4, 1
        on a demand paged virtual memory system running on a computer system that has main memory
        size of 3 page frames which are initially empty. Let LRU, FIFO and OPTIMAL denote the number
        of page faults under the corresponding page replacement policy. Then
        (A) OPTIMAL < LRU < FIFO                                     (B) OPTIMAL < FIFO < LRU
        (C) OPTIMAL = LRU                                            (D) OPTIMAL = FIFO
 Q.43   Suppose R1(A, B) and R2(C, D) are two relation schemas. Let r1 and r2 be the corresponding
        relation instances. B is a foreign key that refers to C in R2. If data in r1 and r2 satisfy referential
        integrity constraints, which of the following is ALWAYS TRUE?
        (A) B(r1)  C(r2) = 
        (B) C(r2)  B(r1) = 
        (C) B(r1) = C(r2)
        (D) B(r1)  C(r2) ≠ 
CS-A                                                                                                                 10/20
GATE CS 2012 question paper, GATE 2012, Computer Science and Information Technology, page 11 of 19
Page 11 of 19
Text of page 11
2012                                                                     COMPUTER SCIENCE & INFORMATION TECH. – CS
 Q.44   Consider a source computer (S) transmitting a file of size 106 bits to a destination computer (D)
        over a network of two routers (R1 and R2) and three links (L1, L2, and L3). L1 connects S to R1; L2
        connects R1 to R2; and L3 connects R2 to D. Let each link be of length 100 km. Assume signals
        travel over each link at a speed of 108 meters per second. Assume that the link bandwidth on each
        link is 1Mbps. Let the file be broken down into 1000 packets each of size 1000 bits. Find the total
        sum of transmission and propagation delays in transmitting the file from S to D?
        (A) 1005 ms             (B) 1010 ms               (C) 3000 ms             (D) 3003 ms
 Q.45   Consider an instance of TCP’s Additive Increase Multiplicative Decrease (AIMD) algorithm where
        the window size at the start of the slow start phase is 2 MSS and the threshold at the start of the first
        transmission is 8 MSS. Assume that a timeout occurs during the fifth transmission. Find the
        congestion window size at the end of the tenth transmission.
        (A) 8 MSS                 (B) 14 MSS                  (C) 7 MSS               (D) 12 MSS
 Q.46   Consider the set of strings on {0,1} in which, every substring of 3 symbols has at most two zeros.
        For example, 001110 and 011001 are in the language, but 100010 is not. All strings of length less
        than 3 are also in the language. A partially completed DFA that accepts this language is shown
        below.

                                                00
                                       0

                                            1
                                   0                     01
                         0

                                                     0        1
                                                                           q          0, 1

                         1                  0
                                   1                     10



                                                11
                                   1


        The missing arcs in the DFA are

        (A)                                                       (B)
                    00       01        10       11        q                     00   01       10    11      q
           00        1        0                                     00                0                     1
           01                                    1                  01                1
           10       0                                               10                               0
           11                          0                            11                0

        (C)                                                       (D)
                    00       01        10       11        q                     00   01       10    11      q
           00                 1                           0         00                1                     0
           01                 1                                     01                               1
           10                          0                            10          0
           11                0                                      11                        0

CS-A                                                                                                            11/20
GATE CS 2012 question paper, GATE 2012, Computer Science and Information Technology, page 12 of 19
Page 12 of 19
Text of page 12
2012                                                              COMPUTER SCIENCE & INFORMATION TECH. – CS

 Q.47   The height of a tree is defined as the number of edges on the longest path in the tree. The function
        shown in the pseudocode below is invoked as height(root) to compute the height of a binary
        tree rooted at the tree pointer root.

        int height (treeptr n)
        { if (n == NULL) return -1;
          if (n  left == NULL)
              if (n  right == NULL) return 0;

                else return         B1    ;                               // Box 1

            else { h1 = height (n  left);
                   if (n  right == NULL) return (1+h1);
                   else { h2 = height (n  right);

                                return   B2     ;                         // Box 2
                            }
                 }
        }

        The appropriate expressions for the two boxes B1 and B2 are
        (A) B1: (1+height(n  right))                   (B) B1: (height(n  right))
            B2: (1+max(h1, h2))                             B2: (1+max(h1,h2))

        (C) B1: height(n  right)                       (D) B1: (1+ height(n  right))
            B2: max(h1, h2)                                 B2: max(h1, h2)




CS-A                                                                                                     12/20
GATE CS 2012 question paper, GATE 2012, Computer Science and Information Technology, page 13 of 19
Page 13 of 19
Text of page 13
2012                                                            COMPUTER SCIENCE & INFORMATION TECH. – CS

Common Data Questions
 Common Data for Questions 48 and 49:

 Consider the following C code segment.

  int a, b, c = 0;
  void prtFun(void);
  main( )
  {   static int a = 1;                         /*    Line 1 */
      prtFun( );
      a += 1;
      prtFun( );
      printf(“ \n %d %d ”, a, b);

  }

  void prtFun(void)
  {   static int a = 2;                        /*    Line 2 */
      int b = 1;
      a += ++b;
      printf(“ \n %d %d ”, a, b);

  }


 Q.48   What output will be generated by the given code segment?

        (A)                   (B)                     (C)                    (D)

         3      1               4         2            4       2              3       1
         4      1               6         1            6       2              5       2
         4      2               6         1            2       0              5       2

 Q.49   What output will be generated by the given code segment if:
        Line 1 is replaced by auto int a = 1;
        Line 2 is replaced by register int a = 2;
        (A)                    (B)                    (C)                    (D)

         3      1               4         2            4       2              4       2
         4      1               6         1            6       2              4       2
         4      2               6         1            2       0              2       0




CS-A                                                                                                 13/20
GATE CS 2012 question paper, GATE 2012, Computer Science and Information Technology, page 14 of 19
Page 14 of 19
Text of page 14
2012                                                             COMPUTER SCIENCE & INFORMATION TECH. – CS
 Common Data for Questions 50 and 51:

 Consider the following relations A, B and C:

             A                                    B                                      C
  Id       Name      Age                  Id     Name      Age                Id       Phone    Area
  12       Arun      60                   15     Shreya    24                 10       2200     02
  15       Shreya    24                   25     Hari      40                 99       2100     01
  99       Rohit     11                   98     Rohit     20
                                          99     Rohit     11

 Q.50   How many tuples does the result of the following relational algebra expression contain? Assume
        that the schema of A∪B is the same as that of A.
        (A∪B) ⋈ A.Id > 40  C.Id < 15 C

        (A)   7                 (B) 4                  (C) 5                  (D) 9

 Q.51   How many tuples does the result of the following SQL query contain?

        SELECT A.Id
        FROM A
        WHERE A.Age > ALL (SELECT B.Age
                           FROM B
                           WHERE B.Name = ‘Arun’)

        (A) 4                   (B) 3                  (C) 0                  (D) 1




CS-A                                                                                                   14/20
GATE CS 2012 question paper, GATE 2012, Computer Science and Information Technology, page 15 of 19
Page 15 of 19
Text of page 15
2012                                                              COMPUTER SCIENCE & INFORMATION TECH. – CS

Linked Answer Questions
 Statement for Linked Answer Questions 52 and 53:
 For the grammar below, a partial LL(1) parsing table is also presented along with the grammar. Entries that
 need to be filled are indicated as E1, E2, and E3.  is the empty string, $ indicates end of input, and, |
 separates alternate right hand sides of productions.
 SaAbB | bAaB | 
 AS
 BS

                     a            b                $
          S         E1            E2             S
          A        AS           AS             error
          B        BS           BS              E3

 Q.52   The FIRST and FOLLOW sets for the non-terminals A and B are

        (A) FIRST(A) = {a, b, } = FIRST(B)              (B) FIRST(A) = {a, b, $}
            FOLLOW(A) = {a, b}                               FIRST(B) = {a, b, }
            FOLLOW(B) = {a, b, $}                            FOLLOW(A) = {a, b}
                                                             FOLLOW(B) = {$}

        (C) FIRST(A) = {a, b, } = FIRST(B)              (D) FIRST(A) = {a, b} = FIRST(B)
            FOLLOW(A) = {a, b}                               FOLLOW(A) = {a, b}
            FOLLOW(B) =                                     FOLLOW(B) = {a, b}
 Q.53   The appropriate entries for E1, E2, and E3 are
        (A) E1: S  aAbB, A  S                          (B) E1: S  aAbB, S  
            E2: S  bAaB, B  S                              E2: S  bAaB, S  
            E3: B  S                                        E3: S  

        (C) E1: S  aAbB, S                            (D) E1: A  S, S  
            E2: S  bAaB, S                                E2: B  S, S  
            E3: B  S                                        E3: B  S

 Statement for Linked Answer Questions 54 and 55:
 A computer has a 256 KByte, 4-way set associative, write back data cache with block size of 32 Bytes. The
 processor sends 32 bit addresses to the cache controller. Each cache tag directory entry contains, in
 addition to address tag, 2 valid bits, 1 modified bit and 1 replacement bit.
 Q.54   The number of bits in the tag field of an address is

        (A) 11                  (B) 14                   (C) 16                 (D) 27

 Q.55   The size of the cache tag directory is
        (A) 160 Kbits            (B) 136 Kbits           (C) 40 Kbits           (D) 32 Kbits




CS-A                                                                                                     15/20
GATE CS 2012 question paper, GATE 2012, Computer Science and Information Technology, page 16 of 19
Page 16 of 19
Text of page 16
2012                                                              COMPUTER SCIENCE & INFORMATION TECH. – CS
General Aptitude (GA) Questions

Q. 56 – Q. 60 carry one mark each.
  Q.56 The cost function for a product in a firm is given by 5q2, where q is the amount of production. The
       firm can sell the product at a market price of 50 per unit. The number of units to be produced by
       the firm such that the profit is maximized is
        (A) 5                   (B) 10                  (C) 15                  (D) 25

  Q.57 Choose the most appropriate alternative from the options given below to complete the following
       sentence:

        Despite several ––––––––– the mission succeeded in its attempt to resolve the conflict.
        (A) attempts            (B) setbacks            (C) meetings            (D) delegations

  Q.58 Which one of the following options is the closest in meaning to the word given below?

        Mitigate
        (A) Diminish            (B) Divulge             (C) Dedicate            (D) Denote

  Q.59 Choose the grammatically INCORRECT sentence:
        (A) They gave us the money back less the service charges of Three Hundred rupees.
        (B) This country’s expenditure is not less than that of Bangladesh.
        (C) The committee initially asked for a funding of Fifty Lakh rupees, but later settled for a lesser
            sum.
        (D) This country’s expenditure on educational reforms is very less.

  Q.60 Choose the most appropriate alternative from the options given below to complete the following
       sentence:

        Suresh’s dog is the one ––––––––– was hurt in the stampede.
        (A) that                (B) which               (C) who                 (D) whom

Q. 61 - Q. 65 carry two marks each.
  Q.61 Wanted Temporary, Part-time persons for the post of Field Interviewer to conduct personal
       interviews to collect and collate economic data. Requirements: High School-pass, must be
       available for Day, Evening and Saturday work. Transportation paid, expenses reimbursed.

        Which one of the following is the best inference from the above advertisement?
        (A) Gender-discriminatory
        (B) Xenophobic
        (C) Not designed to make the post attractive
        (D) Not gender-discriminatory

  Q.62 A political party orders an arch for the entrance to the ground in which the annual convention is
       being held. The profile of the arch follows the equation y = 2x – 0.1x2 where y is the height of the
       arch in meters. The maximum possible height of the arch is
        (A) 8 meters            (B) 10 meters           (C) 12 meters           (D) 14 meters

CS-A                                                                                                     16/20
GATE CS 2012 question paper, GATE 2012, Computer Science and Information Technology, page 17 of 19
Page 17 of 19
Text of page 17
2012                                                                 COMPUTER SCIENCE & INFORMATION TECH. – CS
  Q.63 An automobile plant contracted to buy shock absorbers from two suppliers X and Y. X supplies
       60% and Y supplies 40% of the shock absorbers. All shock absorbers are subjected to a quality test.
       The ones that pass the quality test are considered reliable. Of X’s shock absorbers, 96% are reliable.
       Of Y’s shock absorbers, 72% are reliable.

        The probability that a randomly chosen shock absorber, which is found to be reliable, is made by Y
        is
        (A) 0.288               (B) 0.334                (C) 0.667                (D) 0.720

  Q.64 Which of the following assertions are CORRECT?

        P: Adding 7 to each entry in a list adds 7 to the mean of the list
        Q: Adding 7 to each entry in a list adds 7 to the standard deviation of the list
        R: Doubling each entry in a list doubles the mean of the list
        S: Doubling each entry in a list leaves the standard deviation of the list unchanged
        (A) P, Q                (B) Q, R                 (C) P, R                 (D) R, S

  Q.65 Given the sequence of terms, AD CG FK JP, the next term is
        (A) OV                  (B) OW                   (C) PV                   (D) PW


                               END OF THE QUESTION PAPER




CS-A                                                                                                      17/20
GATE CS 2012 question paper, GATE 2012, Computer Science and Information Technology, page 18 of 19
Page 18 of 19
Text of page 18
GATE 2012 ‐ Answer Key ‐ Paper : CS

Paper   Question no. Code : A         Code : B        Code : C       Code : D
 CS          1       B                C               B              D
 CS          2       C                C               D              C
 CS          3       Marks to All     C               C              C
 CS          4       B                D               D              C
 CS          5       C                D               C              C
 CS          6       A                C               B              C
 CS          7       B                D               A              D
 CS          8       C                C               C              C
 CS          9       D                C               B              D
 CS         10       C                C               Marks to All   D
 CS         11       D                C               C              C
 CS         12       B                C               B              C
 CS         13       C                D               C              B
 CS         14       C                B               D              C
 CS         15       C                C               C              D
 CS         16       D                Marks to All    C              C
 CS         17       D                B               C              D
 CS         18       C                C               C              C
 CS         19       D                A               D              B
 CS         20       C                B               C              A
 CS         21       C                C               D              C
 CS         22       C                D               D              B
 CS         23       C                C               C              Marks to All
 CS         24       D                D               C              C
 CS         25       C                B               C              B
 CS         26       B                C               D              D
 CS         27       B                Marks to All    A              A
 CS         28       B                Marks to All    A              Marks to All
 CS         29       Marks to All     D               B              A
 CS         30       B                B               B              A
 CS         31       C                B               C              B
 CS         32       B                A               B              B
 CS         33       B                A               Marks to All   D
 CS         34       A                Marks to All    B              Marks to All
 CS         35       A                A               B              Marks to All
 CS         36       D                D               B              C
 CS         37       C                B               D              D
 CS         38       Marks to All     B               A              A
 CS         39       Marks to All     B               Marks to All   A
 CS         40       D                Marks to All    A              B
GATE CS 2012 question paper, GATE 2012, Computer Science and Information Technology, page 19 of 19
Page 19 of 19
Text of page 19
GATE 2012 ‐ Answer Key ‐ Paper : CS

Paper   Question no. Code : A         Code : B        Code : C       Code : D
 CS         41       B                B               A              B
 CS         42       B                C               B              C
 CS         43       A                B               B              B
 CS         44       A                B               D              Marks to All
 CS         45       Marks to All     A               Marks to All   B
 CS         46       D                A               Marks to All   B
 CS         47       A                D               C              B
 CS         48       C                D               A              B
 CS         49       D                C               B              A
 CS         50       A                B               C              D
 CS         51       B                A               D              C
 CS         52       A                C               A              C
 CS         53       C                A               C              A
 CS         54       C                A               C              A
 CS         55       A                C               A              C
 CS         56       A                B               A              D
 CS         57       B                A               D              Marks to All
 CS         58       A                D               Marks to All   A
 CS         59       D                Marks to All    A              B
 CS         60       Marks to All     A               B              A
 CS         61       D                B               B              C
 CS         62       B                B               C              A
 CS         63       B                C               A              D
 CS         64       C                A               D              B
 CS         65       A                D               B              B
Page 1 of 19

Source: GATE. Question paper published by GATE.