Computer Science Previous Year Questions

Explanation

A self-dual function is fixed by its values on one half of the input combinations: the 2ⁿ input combinations form 2ⁿ⁻¹ mutually complementary pairs, and the function's value on one member of each pair determines its value on the other. So the number of self-dual functions is 2^(2^(n−1)).

Explanation

Kₘ,ₙ is Hamilton circuit if and only if m = n ≥ 2, (Circuit is a path similar to a cycle that starts and ends at the same vertex) and Kₘ,ₙ is a Hamilton circuit if m = n ≥ 2, so the correct answer is (c).

Explanation

After the two recursive calls in Mergesort complete, but before the merge step, elements in each half of the array are sorted amongst themselves because, Mergesort is possible when two arrays are sorted. If two unsorted arrays are submitted to Mergesort algorithm. It will sort each of them first before merging them, because Mergesort is a divide and conquer algorithm, Hence the answer is option (b).

Explanation

In searching for an element in hash table requires O(1) time for the average time, whereas for direct it holds for the worst-case time. So the correct answer is option (c).

Explanation

When the two modules run one after the other, the total time is h(n) + g(n), which is O(max(h(n), g(n))) because the larger term dominates and lower-order terms are ignored. Hence the answer is (b).

Explanation

N! < nⁿ for all n ≥ 1, so n! is O(nⁿ). Using Stirling's approximation, log(n!) ≈ n log n − n + O(log n), so log n! is O(n log n). Therefore, the correct answer is (b) O(nⁿ) and O(n log n).

Explanation

Base address of an array is the starting address of an array. One can easily access to all the cells of an array if information about this can be achieved.

Explanation

Parameter of a while statement in a languages takes two values true in the form of non-zero and false in the form of zero. Here 87 is a non-zero value and hence the while block gets true for infinite times.

Explanation

Unrelated class means the classes are not connected via inheritance. But a relation can be achieved between two unrelated classes through friend function.

Explanation

0 is the identifier for a program to inform the operating system (OS) about proper running of a program. Each of the non-zero value signifies unique error doing running of a program.

Explanation

External level (highest level). It is the user's view of the database and it describes part of the database for Particular group of user and provides a powerful and flexible security mechanism by hiding part of the database from certain users. The user is not aware of the existence of any attribute that are missing from the view. It permits user to access data in a way that is customized to their needs. So that the same data can be seen by different user in different ways, at the same time.

Explanation

Clustered index determines the order in which the rows of a table are stored on disk. If a table has a clustered index. Then the rows of that table will be stored on disk in the same exact order as the clustered index. In some cases, the index is created on non-primary key columns which may not be unique for each record. Clustering index is defined as an ordered data files.

Explanation

A relation is in BCNF, if and only if, every determinant is a candidate key i.e. the left hand side of every non trivial dependency is a super key or there is a trivial dependency or both. After 3NF, there may arise a situation that two candidate keys are having one attribute in common (overlapping) and this overlapping must be cleared to satisfy BCNF. A prime attribute (an attribute that is a part of a candidate key) can on depend on a super key. So a prime attribute cannot be transitively dependent on a key in BCNF relation. So the false statement is option (d).

Explanation

Bit rate = number of bits per unit time; baud rate = number of signal units per unit time. Here each signal unit carries 6 bits, so baud rate = bit rate / 6 = 3000/6 = 500 baud/sec.

Explanation

The original ethernet IEEE 802.3 standard define the minimum ethernet frame size as 64 bytes and maximum as 1518 bytes. Where payload size in ethernet defined the minimum 46 bytes and maximum 1500 bytes.

Explanation

A bridge functions in the data link layer, which means it cannot read IP addresses; it has access to the physical (MAC) addresses of all stations connected to it.

Explanation

Key Process Area (KPA) used in CMM identifies a cluster of related activities that, when performed collectively, achieve a set of goals considered important.

Explanation

There are 14 relative complexity adjustment factor are (1) Requirement for reliable backup and recovery (2) Require for data communication (3) Extent of distributing processing (4) Performance requirement (5) Expected operational environment (6) Extent of online data entries (7) Extent of multi-operation online data input. (8) Extent of online updating of master files. (9) Extent of complex inputs, outputs. (10) Extent of complex data processing. (11) Extent of currently developed code can be designed for reuse. (12) Extent of conversion and installation in the design. (13) Extent of multiple installation in an organization. (14) Extent of change and focus on ease of use.

Explanation

Software architecture refers to the high level structure of software system, the discipline of creating such structures, and the documentation.

Explanation

Object request broker (ORB) is middleware that uses the CORBA (Common Object Request Broker Architecture) specification. The ORB takes care of all of the details in routing a request from client to object and the response to its destination. ORB runs on clients as well as on the application server.

Explanation

A software agent is a piece of software that function as a agent for a user or another program, working autonomously and continuously in a particular environment. It is inhibited by other processes and agents, but it is also able to learn from its experience in functioning in an environment over a long period of time.

Explanation

Regression testing is the process of testing changes to computer program to make sure that the older programming still works with the new changes. This happens only in case of maintenance. So it relates to the maintenance testing, hence the answer is option (d).

Explanation

The for loop "for n in one two three; do echo -n $n; done" iterates n over the words one, two and three and echoes each, so it gives the output "one two three". So the answer is (c).

Explanation

Risk management is the Process of identifying, controlling threats to an organization's capital and earning. Risk management can be considered as dealing with the possibility and actual occurrence of those events that are not regular expected and information hiding is the principle of segregation of the design decision in a computer program that are most like to change, thus protecting other parts of the program from extensive modification if the design decision is changed.

Explanation

Removing left recursion and left factoring the grammar do not suffice to convert an arbitrary CFG to an LL(1) grammar. LL(1) parsing is top-down; for it the grammar must also be unambiguous and deterministic (e.g. an ambiguous grammar stays non-LL(1)), besides being free from left recursion.

Explanation

In a JK flip-flop, when J = 1 and K = 1, Q toggles between 0 and 1 continuously as long as the clock is enabled, so the final value of Q is uncertain (race condition). The master-slave JK flip-flop is used to resolve this problem.

Explanation

There are 2 types of circuits: (1) Combinational and (2) Sequential. Combinational circuits are those whose outputs depend only upon the current input, like adder, subtractor, MUX, DEMUX etc. Sequential circuits are those whose output depends on both current and previous inputs. Hence the answer is (c).

Explanation

Μ~A(x) = 1 − μA(x) for all x ∈ U. The given set A can be seen as A = {(1, 0), (2, 0), (3, 0.7), (4, 0), (5, 1), (6, 0.8), (7, 0)}. So the complement of A is {(1, 1), (2, 1), (3, 0.3), (4, 1), (6, 0.2), (7, 1)} (element 5 has membership 0). Hence the answer is (c).

Explanation

Memory capacity is 2ᵐ Kbytes = 2^(m+10) bytes, so the whole memory can be addressed with m + 10 bits. 2ⁿ operations can be represented by n bits. An instruction of the form OP, operand₁, operand₂, operand₃ will therefore take 3(m + 10) + n = 3m + n + 30 bits. So the answer is (d).

Explanation

New processes arrive at 5 per minute, i.e. one process every 60/5 = 12 seconds. Each process needs 6 seconds of service time. CPU utilization = (total service time required / total available time) × 100 = (6/12) × 100 = 50%. Hence the right option is (b).

Explanation

Ν₀ = 200 failures, μ = 100 failures, λ₀ = 20 failures/CPU hr. Current failure intensity = λ₀(1 − μ/ν₀) = 20(1 − 100/200) = 20(1 − 0.5) = 10 failures/CPU hr. So the answer is (b).

Explanation

In register indirect addressing the address of the operand is held in a register, so memory can be referenced without having a full memory address in the instruction. Hence the answer is (d).

Explanation

A microprocessor is a computer processor which incorporates the functions of a computer's control processing unit (CPU) on a single integrated circuit (IC), or at most a few integrated circuits. A microcomputer is small, relatively, inexpensive computer with a microprocessor as its control processing unit (CPU). It includes a microprocessor, memory, and minimal input/output (I/O) circuitry mounted on a single printed circuit board. That means, microprocessor does not contain input/output devices.

Explanation

((A + B) ∗ C + D) / (E + F + G) → (AB+ ∗ C + D) / (E + F + G) → (AB+C∗ + D) / (E + F + G) → AB+C∗D+ / (EF+ + G) → AB+C∗D+ / EF+G+ → AB+C∗D+EF+G+/ Hence, the answer is (a).

Explanation

It is a search algorithm that seeks to decrease the number nodes that are evaluated by the Min-max algorithm in its search tree. It is an adversial search algorithm used commonly for machine playing of two-player games.

Explanation

In Quicksort, the depth of a leaf depends on how the input size reduces at each level. If the split is always in the ratio (1 − α) to α, the minimum depth corresponds to the path where the recursion always follows the smaller partition, i.e. of size αn. At each level the size becomes n, αn, α²n, α³n, … We stop when the size becomes 1: αᵏn = 1 ⇒ k log α + log n = 0 ⇒ k = −lg n / lg α. Hence the answer is (c).

Explanation

This is a theorem in universal hashing: if h is chosen from a universal collection and is used to hash n keys into a table of size m, where n ≤ m, the expected number of collisions involving a particular key is less than 1. So the answer is (a).

Explanation

Code blocks not only allow many algorithms to be implemented with clarity, elegance and efficiency, but also help the programmer better conceptualize the true nature of the algorithm being implemented. So the answer is (b).

Explanation

The greedy algorithm work in a way that it has same estimate (called a heuristic) of how for from the goal any vertex is. Instead of selecting the vertex closet to the starting point, it selects the vertex closet to the goal, so the answer is (c).

Explanation

(a) DES : DES is an implementation of a fiestel cipher. It uses 16 round fiestel structure. DES has an effective key length of 56 bits. (b) AES : The more popular and widely adopted symmetric encryption algorithm is AES. The features of AES is symmetric key symmetric block cipher and it has 128 bit key. (c) RSA : RSA algorithm works on two different keys i.e public key & private key. As the name public key given to everyone & private key is kept private. (d) SHA-1 : It is message digest.

Explanation

T(n) = 3T(n/4) + n. Here a = 3, b = 4, f(n) = n and n^(log₄3) ≈ n^0.79. Since f(n) = n grows polynomially faster than n^(log₄3), case 3 of the master theorem gives T(n) = Θ(n). So T(n) = O(n) (it is also O(n²), but (c) is the tight bound and the best choice).

Explanation

P₁/w₁ = 5, p₂/w₂ = 2.5, p₃/w₃ = 2, p₄/w₄ = 2. Select object 1 (profit 10), then object 2 (profit 10). Objects 3 and 4 have the same ratio, but object 4 gives more profit and fits exactly: total weight = 2 + 4 + 9 = 15. Maximum profit = 10 + 10 + 18 = 38. So the answer is (b).

Explanation

Fopen() : creates a file or opens an existing file and returns a file pointer, e.g. FILE ∗fp; fp = fopen("<file-name>", "<mode>"); fclose() : closes a file; returns 0 on success and EOF otherwise. ferror() : checks the error indicator for the given file stream, returning non-zero if set and 0 otherwise. feof() : checks the end-of-file indicator for the given file stream, returning non-zero if set and 0 otherwise.

Explanation

Small talk was one of the earliest OOP's language (with other like simulate and Eiffel) and can be said to be extremely "Pure" in an OOP sense. In small talk everything is an object and objects are only communicated with via the sending of message. Hence the answer is (a).

Explanation

CaptureEvents (EventType) method instructs the window to capture all events of a particular type.

Explanation

Object oriented development makes software closet to abstractions the exists in the real world and the term object oriented means that software is a collection of discrete objects that incorporate both data structure and behaviour.

Explanation

Simulating LRU with 4 frames gives 10 page replacements (faults after the frames are filled), and the optimal page replacement algorithm gives 7 replacements. So the correct answer is (b).

Explanation

Option (b) is NOT CORRECT as the number of request for disk drive can be greatly influenced by file allocation method.

Explanation

Super block describes the state of file system, the total size of partition, the block size, pointers to a list of free blocks, the node number of root directory, magic number etc.

Explanation

The design of virtual memory assumes that the underlying hardware supports virtual to physical mapping.