GATE Computer Science

GATE 2025 Computer Science and Information Technology CS-2 (Afternoon) (English)

GATE Computer Science Previous Year Question Papers — GATE 2025 Computer Science and Information Technology CS-2 (Afternoon) (English). Official GATE Computer Science question-paper PDFs: 2024-2026 from the live organising-institute sites, and 2007-2023 from Internet Archive captures of the IIT Kanpur, IIT Kharagpur, IISc and IIT Guwahati GATE archives that once republished every earlier paper, with the official answer key wherever the same host captured one. Reviewed questions and answers are published for 2024-2025; the remaining years are PDF-only.

Paper details

Year: 2025
Shift: Cs2
Language: English

Validated source link: GATE (rotating organising institute) (retrieved 2026-08-23).

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Question 16

Consider the following statements: (i) Address Resolution Protocol (ARP) provides a mapping from an IP address to the corresponding hardware (link-layer) address. (ii) A single TCP segment from a sender S to a receiver R cannot carry both data from S to R and acknowledgement for a segment from R to S. Which ONE of the following is CORRECT?

Both (i) and (ii) are TRUE
(i) is TRUE and (ii) is FALSE
(i) is FALSE and (ii) is TRUE
Both (i) and (ii) are FALSE

Official answer and source attribution

Answer: (i) is TRUE and (ii) is FALSE

Official answer: option B. Source: GATE 2025 CS-2, Q.16 (IIT Roorkee final answer key).

Question 18

A machine receives an IPv4 datagram. The protocol field of the IPv4 header has the protocol number of a protocol X. Which ONE of the following is NOT a possible candidate for X?

Internet Control Message Protocol (ICMP)
Internet Group Management Protocol (IGMP)
Open Shortest Path First (OSPF)
Routing Information Protocol (RIP)

Official answer and source attribution

Answer: Routing Information Protocol (RIP)

Official answer: option D. Source: GATE 2025 CS-2, Q.18 (IIT Roorkee final answer key).

Question 20

Consider an unordered list of N distinct integers. What is the minimum number of element comparisons required to find an integer in the list that is NOT the largest in the list?

1
N−1
N
2N−1

Official answer and source attribution

Answer: 1

Official answer: option A. Source: GATE 2025 CS-2, Q.20 (IIT Roorkee final answer key).

Question 36

Suppose we are transmitting frames between two nodes using Stop-and-Wait protocol. The frame size is 3000 bits. The transmission rate of the channel is 2000 bps (bits/second) and the propagation delay between the two nodes is 100 milliseconds. Assume that the processing times at the source and destination are negligible. Also, assume that the size of the acknowledgement packet is negligible. Which ONE of the following most accurately gives the channel utilization for the above scenario in percentage?

88.23
93.75
85.44
66.67

Official answer and source attribution

Answer: 88.23

Official answer: option A. Source: GATE 2025 CS-2, Q.36 (IIT Roorkee final answer key).

Question 37

Let G be an edge-weighted undirected graph with positive edge weights. Suppose a positive constant α is added to the weight of every edge. Which ONE of the following statements is TRUE about the minimum spanning trees (MSTs) and shortest paths (SPs) in G before and after the edge weight update?

Every MST remains an MST, and every SP remains an SP.
MSTs need not remain MSTs, and every SP remains an SP.
Every MST remains an MST, and SPs need not remain SPs.
MSTs need not remain MSTs, and SPs need not remain SPs.

Official answer and source attribution

Answer: Every MST remains an MST, and SPs need not remain SPs.

Official answer: option C. Source: GATE 2025 CS-2, Q.37 (IIT Roorkee final answer key).

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Question 38

A meld operation on two instances of a data structure combines them into one single instance of the same data structure. Consider the following data structures: P: Unsorted doubly linked list with pointers to the head node and tail node of the list. Q: Min-heap implemented using an array. R: Binary Search Tree. Which ONE of the following options gives the worst-case time complexities for meld operation on instances of size n of these data structures?

P: Θ(1), Q: Θ(n), R: Θ(n)
P: Θ(1), Q: Θ(nlog n), R: Θ(n)
P: Θ(n), Q: Θ(nlog n), R: Θ(n^2)
P: Θ(1), Q: Θ(n), R: Θ(nlog n)

Official answer and source attribution

Answer: P: Θ(1), Q: Θ(n), R: Θ(n)

Official answer: option A. Source: GATE 2025 CS-2, Q.38 (IIT Roorkee final answer key).

Question 39

For a direct-mapped cache, 4 bits are used for the tag field and 12 bits are used to index into a cache block. The size of each cache block is one byte. Assume that there is no other information stored for each cache block. Which ONE of the following is the CORRECT option for the sizes of the main memory and the cache memory in this system (byte addressable), respectively?

64 KB and 4 KB
128 KB and 16 KB
64 KB and 8 KB
128 KB and 6 KB

Official answer and source attribution

Answer: 64 KB and 4 KB

Official answer: option A. Source: GATE 2025 CS-2, Q.39 (IIT Roorkee final answer key).

Question 41

An array A of length n with distinct elements is said to be bitonic if there is an index 1 ≤i≤n such that A[1. . i] is sorted in the non-decreasing order and A[i+ 1 . . n] is sorted in the non-increasing order. Which ONE of the following represents the best possible asymptotic bound for the worst-case number of comparisons by an algorithm that searches for an element in a bitonic array A?

Θ(n)
Θ(1)
Θ(log^2 n)
Θ(log n)

Official answer and source attribution

Answer: Θ(log n)

Official answer: option D. Source: GATE 2025 CS-2, Q.41 (IIT Roorkee final answer key).