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GATE CS - Previous Year Questions

Actual GATE CS exam questions from previous years (2020-2025)

142 questions•15 pages•~213 min

Progress: 0 / 1420%

Page 1 of 15 • Questions 1-10 of 142

Q1medium

[GATE CS 2025 Set-1 Q11] Suppose a program is running on a non-pipelined single processor computer system. The computer is connected to an external device that can interrupt the processor asynchronously. The processor needs to execute the interrupt service routine (ISR) to serve this interrupt. The following steps (not necessarily in order) are taken by the processor when the interrupt arrives: (i) The processor saves the content of the program counter. (ii) The program counter is loaded with the start address of the ISR. (iii) The processor finishes the present instruction. Which ONE of the following is the CORRECT sequence of steps?

A)(iii), (i), (ii)

B)(i), (iii), (ii)

C)(i), (ii), (iii)

D)(iii), (ii), (i)

Q2medium

[GATE CS 2025 Set-1 Q12] Which ONE of the following statements is FALSE regarding the symbol table?

A)Symbol table is responsible for keeping track of the scope of variables.

B)Symbol table can be implemented using a binary search tree.

C)Symbol table is not required after the parsing phase.

D)Symbol table is created during the lexical analysis phase.

Q3medium

[GATE CS 2025 Set-1 Q13] Which ONE of the following techniques used in compiler code optimization uses live variable analysis?

A)Run-time function call management

B)Register assignment to variables

C)Strength reduction

D)Constant folding

Q4medium

[GATE CS 2025 Set-1 Q14] Consider a demand paging memory management system with 32-bit logical address, 20-bit physical address, and page size of 2048 bytes. Assuming that the memory is byte addressable, what is the maximum number of entries in the page table?

A)221

B)220

C)222

D)224

Q5medium

[GATE CS 2025 Set-1 Q15] A schedule of three database transactions 𝑇 , 𝑇 , and 𝑇 is shown. 𝑅 (𝐴) and 1 2 3 𝑖 𝑊(𝐴) denote read and write of data item 𝐴 by transaction 𝑇,𝑖 = 1,2,3. The 𝑖 𝑖 transaction 𝑇 aborts at the end. Which other transaction(s) will be required to be 1 rolled back? 𝑅 (𝑋) 𝑊 (𝑌) 𝑅 (𝑋) 𝑅 (𝑌) 𝑅 (𝑌) 𝐴𝐵𝑂𝑅𝑇(𝑇 ) 1 1 2 2 3 1

A)Only 𝑇 2

B)Only 𝑇 3

C)Both 𝑇 and 𝑇 2 3

D)Neither 𝑇 nor 𝑇 2 3

Q6medium

[GATE CS 2025 Set-1 Q16] Identify the ONE CORRECT matching between the OSI layers and their corresponding functionalities as shown. OSI Layers Functionalities (a) Network layer (I) Packet routing (b) Transport layer (II) Framing and error handling (c) Datalink layer (III) Host to host communication

A)(a)-(I), (b)-(II), (c)-(III)

B)(a)-(I), (b)-(III), (c)-(II)

C)(a)-(II), (b)-(I), (c)-(III)

D)(a)-(III), (b)-(II), (c)-(I)

Q7medium

[GATE CS 2025 Set-1 Q17] 𝑔(.) is a function from 𝐴 to 𝐵, 𝑓(.) is a function from 𝐵 to 𝐶, and their composition defined as 𝑓(𝑔(.)) is a mapping from 𝐴 to 𝐶. If 𝑓(.) and 𝑓(𝑔(.)) are onto (surjective) functions, which ONE of the following is TRUE about the function 𝑔(.)?

A)𝑔(.) must be an onto (surjective) function.

B)𝑔(.) must be a one-to-one (injective) function.

C)𝑔(.) must be a bijective function, that is, both one-to-one and onto.

D)𝑔(.) is not required to be a one-to-one or onto function.

Q8medium

[GATE CS 2025 Set-1 Q18] Let 𝐺 be any undirected graph with positive edge weights, and 𝑇 be a minimum spanning tree of 𝐺. For any two vertices, 𝑢 and 𝑣, let 𝑑 (𝑢,𝑣) and 𝑑 (𝑢,𝑣) be the 1 2 shortest distances between 𝑢 and 𝑣 in 𝐺 and 𝑇, respectively. Which ONE of the options is CORRECT for all possible 𝐺, 𝑇, 𝑢 and 𝑣?

A)𝑑 (𝑢,𝑣) = 𝑑 (𝑢,𝑣) 1 2

B)𝑑 (𝑢,𝑣) ≤ 𝑑 (𝑢,𝑣) 1 2

C)𝑑 (𝑢,𝑣) ≥ 𝑑 (𝑢,𝑣) 1 2

D)𝑑 (𝑢,𝑣) ≠ 𝑑 (𝑢,𝑣) 1 2

Q9medium

[GATE CS 2025 Set-1 Q19] Consider the following context-free grammar 𝐺, where 𝑆, 𝐴, and 𝐵 are the variables (non-terminals), 𝑎 and 𝑏 are the terminal symbols, 𝑆 is the start variable, and the rules of 𝐺 are described as: 𝑆 → 𝑎𝑎𝐵 | 𝐴𝑏𝑏 𝐴 → 𝑎 | 𝑎𝐴 𝐵 → 𝑏 | 𝑏𝐵 Which ONE of the languages 𝐿(𝐺) is accepted by 𝐺?

A)𝐿(𝐺) = {𝑎2𝑏𝑛 | 𝑛 ≥ 1}∪{𝑎𝑛𝑏2 | 𝑛 ≥ 1}

B)𝐿(𝐺) = {𝑎𝑛𝑏2𝑛 | 𝑛 ≥ 1}∪{𝑎2𝑛𝑏𝑛 | 𝑛 ≥ 1}

C)𝐿(𝐺) = {𝑎𝑛𝑏𝑛 | 𝑛 ≥ 1}

D)𝐿(𝐺) = {𝑎2𝑛𝑏2𝑛 | 𝑛 ≥ 1}

Q10medium

[GATE CS 2025 Set-1 Q20] 𝑇(𝑛) = 2𝑇(𝑛−1)+𝑛2𝑛 for 𝑛 > 0, 𝑇(0) = 1. W hich ONE of the following options is CORRECT?

A)𝑇(𝑛) = Θ(𝑛22𝑛)

B)𝑇(𝑛) = Θ(𝑛2𝑛)

C)𝑇(𝑛) = Θ((log𝑛)22𝑛)

D)𝑇(𝑛) = Θ(4𝑛)

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