Consider the control flow graph given below. [figure] Which one of the following options is the set of live variables at the exit point of each basic block?

(A) B1:\{a,b,c,e,f\},\ B2:\{d,e\},\ B3:\{b,c,e,f\},\ B4:\emptyset

(B) B1:\emptyset,\ B2:\{d,e\},\ B3:\{a,c,f\},\ B4:\emptyset

(C) B1:\{a,b,c,e,f\},\ B2:\{d,e\},\ B3:\{c,e,f\},\ B4:\emptyset

(D) B1:\emptyset,\ B2:\{d,e,f\},\ B3:\{a,b,c,e,f\},\ B4:\emptyset

Consider the following two finite automata D1 and D2. [figure] Which of the following statements is/are true?

(C) L(D1) \cap L(D2) = \{\epsilon\}

(D) (L(D1) \cup L(D2))^ consists of all strings in \{0,1\}^ whose length is divisible by 3

(B) L(D1) is a proper subset of L(D2)

GATE 2026 CS (Set 2) question paper PDF and answer key

The official GATE 2026 Computer Science & Information Technology (Set 2) paper, organised by IIT Guwahati: 65 questions for 100 marks in 3 hours. Download the official question paper and answer key as PDFs. Below is how the marks were split by topic, the complete official answer key and 5 questions solved step by step.

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Question paper (PDF)Official answer key (PDF)

Source: the official paper and answer key published by IIT Guwahati for GATE 2026 (official GATE site). Spotted a mistake? Email team@lemyte.com.

General Aptitude: 10 · 15 marks
Computer Science & Information Technology: 55 · 85 marks
MCQ / MSQ / NAT: 35 / 11 / 19
Marks to all: None

Not in 2027 1 question (Q 29) is on topics removed from the GATE 2027 syllabus. They are marked in the answer key below. What changed for CS

Where the marks were

GATE 2026 CS (Set 2) topic-wise marks

Computer Science & Information Technology questions only; General Aptitude adds 15 marks on top. The top three topics carried 31 of the 85 subject marks.

Topic	Questions	Marks
Programming and Data Structures	7	11
Computer Organization and Architecture	6	10
Algorithms	7	10
Operating System	5	9
Computer Networks	6	9
Databases	4	6
Theory of Computation	4	6
Digital Logic	4	6
Compiler Design	3	5
Discrete Mathematics	3	4
Probability and Statistics	2	3
Calculus	2	3
Linear Algebra	2	3

Free solved questions

5 solved questions from GATE 2026 CS (Set 2)

Question text and figures as in the official paper, the answer from the official key, and a worked solution. The other 60 solutions are in your report after you take the paper.

Q9 · General Aptitude · MCQ · 2 marks

Figures (i) and (ii) represent intercity highway systems. The black dots represent cities and the line segments between them represent intercity highways.

A salesperson needs to make a trip. She needs to start from a city, visit each of the remaining cities exactly once, and finally return to the same city from which she started.

Which one of the following options is then true?

Figure for GATE 2026 CS (Set 2) question 9 (Analytical Aptitude)

(A)
Such a trip is possible for (i), but not for (ii).
(B)
Such a trip is possible for (ii), but not for (i).
(C)
Such a trip is possible for both (i) and (ii).
(D)
Such a trip is possible neither for (i) nor for (ii).

Answer (official key): A

Solution

This is a figure-dependent Hamiltonian-cycle question. The official accepted answer is Option A.

A full graph-theoretic justification can be added later if you want the final polished explanation.

Q10 · General Aptitude · MCQ · 2 marks

An unbiased six-faced dice whose faces are marked with numbers 1, 2, 3, 4, 5, and 6 is rolled twice in succession and the number on the top face is recorded each time. The probability that the sum of the two recorded numbers is a prime number is ________

(A)
3/36
(B)
13/36
(C)
15/36
(D)
19/36

Answer (official key): C

Solution

Possible prime sums are

2,3,5,7,11.

Counts:

sum 2: 1 way
sum 3: 2 ways
sum 5: 4 ways
sum 7: 6 ways
sum 11: 2 ways

Total favorable outcomes:

1+2+4+6+2=15.

Total outcomes:

6 \times 6=36.

So the probability is

\frac{15}{36}.

Therefore, the correct answer is Option C.

Q43 · Compiler Design · MCQ · 2 marks

Consider the control flow graph given below.

Control Flow Graph for Q45

Which one of the following options is the set of live variables at the exit point of each basic block?

(A)
$B1:\{a,b,c,e,f\},\ B2:\{d,e\},\ B3:\{b,c,e,f\},\ B4:\emptyset$
(B)
$B1:\emptyset,\ B2:\{d,e\},\ B3:\{a,c,f\},\ B4:\emptyset$
(C)
$B1:\{a,b,c,e,f\},\ B2:\{d,e\},\ B3:\{c,e,f\},\ B4:\emptyset$
(D)
$B1:\emptyset,\ B2:\{d,e,f\},\ B3:\{a,b,c,e,f\},\ B4:\emptyset$

Answer (official key): A

Solution

This is a figure-dependent liveness-analysis question. The official accepted answer is Option A.

A full IN/OUT set derivation for each block can be added later if you want the complete data-flow solution.

Q44 · Theory of Computation · MSQ · 2 marks

Consider the following two finite automata $D_1$ and $D_2$ .

Finite Automata for Q47

Which of the following statements is/are true?

(A)
$L(D_1) = L(D_2)$
(B)
$L(D_1)$ is a proper subset of $L(D_2)$
(C)
$L(D_1) \cap L(D_2) = \{\epsilon\}$
(D)
$(L(D_1) \cup L(D_2))^*$ consists of all strings in $\{0,1\}^*$ whose length is divisible by 3

Answer (official key): C, D

Solution

This is a figure-dependent finite-automata language question. The official accepted answers are C and D.

A full language characterization for both automata can be added later if you want the final polished explanation.

Q51 · Computer Networks · Numerical · 2 marks

Consider a new TCP connection between a sender and a receiver. The receiver advertised window is constant at 48 KB, the maximum segment size (MSS) is 2 KB, and the slow start threshold for TCP congestion control is 16 KB. Assume that there are no timeouts or duplicate acknowledgements. The number of rounds of transmission required for the congestion control algorithm of the TCP connection to reach the congestion avoidance phase is ____________. (answer in integer)

Note: 1K = $2^{10}$

Answer (official key): 4

Solution

Initially TCP slow start begins with

\text{cwnd} = 1 \text{ MSS} = 2 \text{ KB}.

The slow start threshold is:

16 \text{ KB} = 8 \text{ MSS}.

So the congestion window grows across rounds as:

Round 1: 1 MSS
Round 2: 2 MSS
Round 3: 4 MSS
Round 4: 8 MSS

At this point the threshold is reached and the algorithm enters congestion avoidance. The receiver window of 48 KB does not constrain this early growth.

Therefore, the answer is 4.

The other 60 questions are solved in your report when you take GATE 2026 CS (Set 2) as a 3-hour test.

Take GATE 2026 CS (Set 2) as a test

Official answer key

GATE 2026 CS (Set 2) answer key

All 65 answers from the official key. Numerical answers are ranges; “or” means the key accepts either answer.

Download the official GATE 2026 CS (Set 2) answer key (PDF)

Q	Topic	Type	Marks	Answer
1	Analytical Aptitude	MCQ	1	C
2	Quantitative Aptitude	MCQ	1	A
3	Verbal Aptitude	MCQ	1	A
4	Quantitative Aptitude	MCQ	1	A
5	Spatial Aptitude	MCQ	1	C
6	Verbal Aptitude	MCQ	2	A
7	Analytical Aptitude	MCQ	2	B
8	Spatial Aptitude	MCQ	2	A
9	Analytical Aptitude	MCQ	2	A
10	Quantitative Aptitude	MCQ	2	C
11	Programming and Data Structures	MCQ	1	C
12	Databases	MCQ	1	A
13	Theory of Computation	MCQ	1	D
14	Probability and Statistics	MCQ	1	B
15	Programming and Data Structures	MCQ	1	A
16	Computer Organization and Architecture	MCQ	1	C
17	Programming and Data Structures	MCQ	1	A
18	Databases	MCQ	1	C
19	Digital Logic	MCQ	1	B
20	Discrete Mathematics	MCQ	1	A
21	Operating System	MCQ	1	B
22	Calculus	MSQ	1	A, C
23	Algorithms	Numerical	1	3
24	Discrete Mathematics	MSQ	1	A, B, C
25	Digital Logic	MSQ	1	B, D
26	Computer Networks	MCQ	1	B
27	Algorithms	MSQ	1	A, B
28	Theory of Computation	MSQ	1	B, C
29	Computer NetworksNot in GATE 2027 syllabus: ARP, DHCP and ICMP	MCQ	1	C
30	Algorithms	MCQ	1	A
31	Linear Algebra	Numerical	1	24
32	Compiler Design	Numerical	1	13
33	Computer Organization and Architecture	Numerical	1	-60.25
34	Computer Networks	Numerical	1	4094
35	Algorithms	Numerical	1	3
36	Digital Logic	MCQ	2	B
37	Discrete Mathematics	MCQ	2	C
38	Algorithms	MCQ	2	A
39	Algorithms	MCQ	2	A
40	Algorithms	MCQ	2	A
41	Databases	MCQ	2	A
42	Computer Organization and Architecture	MCQ	2	B
43	Compiler Design	MCQ	2	A
44	Theory of Computation	MSQ	2	C, D
45	Databases	MCQ	2	D
46	Programming and Data Structures	MSQ	2	A, B
47	Compiler Design	MCQ	2	D
48	Theory of Computation	MSQ	2	A, C, D
49	Computer Networks	MCQ	2	D
50	Programming and Data Structures	MSQ	2	A, C
51	Computer Networks	Numerical	2	4
52	Linear Algebra	Numerical	2	48
53	Computer Organization and Architecture	Numerical	2	128
54	Programming and Data Structures	Numerical	2	1
55	Digital Logic	Numerical	2	6
56	Operating System	Numerical	2	16417
57	Probability and Statistics	Numerical	2	0.5
58	Operating System	MSQ	2	A, B, C
59	Programming and Data Structures	Numerical	2	9
60	Operating System	Numerical	2	3
61	Operating System	Numerical	2	1536
62	Calculus	Numerical	2	40
63	Computer Organization and Architecture	MSQ	2	A, B
64	Computer Networks	Numerical	2	30
65	Computer Organization and Architecture	Numerical	2	2.3 to 2.4

Questions about GATE 2026 CS (Set 2)

How many questions are in the GATE 2026 CS (Set 2) paper?

65 questions for 100 marks: 10 General Aptitude questions worth 15 marks and 55 Computer Science & Information Technology questions worth 85 marks. By type, there were 35 MCQs, 11 MSQs, 19 numerical answer (NAT) questions. The paper lasted 3 hours.

Is there negative marking in GATE 2026 CS (Set 2)?

Yes, for MCQs only. A wrong MCQ answer costs one-third of its marks (−⅓ for a 1-mark question, −⅔ for a 2-mark question). MSQ and numerical (NAT) questions have no negative marking, and an MSQ earns marks only when every correct option is chosen.

Which topics carried the most marks in GATE 2026 CS (Set 2)?

Outside General Aptitude, the biggest topics were Programming and Data Structures (11 marks), Computer Organization and Architecture (10 marks), Algorithms (10 marks). The full topic-wise split is in the table on this page.

Were any GATE 2026 CS (Set 2) questions awarded marks to all?

No. Every question was graded with the answer in the official key.

Where does this GATE 2026 CS (Set 2) answer key come from?

From the official answer key published by IIT Guwahati, which organised GATE 2026. Range answers for numerical questions and questions with more than one accepted answer are kept exactly as the key gives them.

GATE 2026 CS (Set 2) question paper PDF and answer key

GATE 2026 CS (Set 2) topic-wise marks

5 solved questions from GATE 2026 CS (Set 2)

GATE 2026 CS (Set 2) answer key

Questions about GATE 2026 CS (Set 2)

How many questions are in the GATE 2026 CS (Set 2) paper?

Is there negative marking in GATE 2026 CS (Set 2)?

Which topics carried the most marks in GATE 2026 CS (Set 2)?

Were any GATE 2026 CS (Set 2) questions awarded marks to all?

Where does this GATE 2026 CS (Set 2) answer key come from?

More GATE papers