Indian Institute of Technology Madras
BS Degree Programme · Examination & Study Paper
Advanced Algorithms
All 2025 papers
Examination Instructions & Guidelines
- Solve on notebook/paper first before checking solutions.
- MCQ: Exactly 1 option is correct. Negative marking applies.
- MSQ: One or more options correct. Select all to score.
- NAT: Numerical response. No negative marking.
- Scientific calculator allowed for all calculations.
- Official answer key is sealed at the end of this sheet.
End Term · 31 Aug 2025 (FN)End Term
- Q1MCQ3 Marks·Choose one option

- ANeither algorithm always correctly determines whether or not a given tree graph has a perfect matching.
- BBoth algorithms always correctly determine whether or not a given tree graph has a perfect matching.
- CAlgorithm B always correctly determines whether or not a given tree graph has a perfect matching; algorithm A does not.
- DAlgorithm A always correctly determines whether or not a given tree graph has a perfect matching; algorithm B does not.
Read the passage below, then answer Q2–Q6

Based on the above data, answer the given subquestions.
Q2MCQ2 Marks·Choose one option
- A3^n
- B2^n
- Cn^3
- Dn^2
- Q3MCQ2 Marks·Choose one option

- A2^n
- Bn
- C1
- D0
- Q4MCQ2 Marks·Choose one option

- A3^n
- B2^n
- C1
- D0
- Q5NAT2 Marks·Write the number
For n = 4, calculate the number of sequences of length 4 consisting only of numbers 0, 1, and 2 such that each number occurs at least once.
Your answer: - Q6NAT2 Marks·Write the number
For n = 5, calculate the number of sequences of length 5 consisting only of numbers 0, 1, and 2 such that each number occurs at least once.
Your answer: - Q7MSQ3 Marks·Choose all correct options

- AIt is in P.
- BIt is in NP.
- CIt is NP-hard.
- DIt is NP-complete.
- Q8MSQ3 Marks·Choose all correct options
Choose the correct options:
- A

- B

- C

- A
- Q9MCQ2 Marks·Choose one option

- ATRUE
- BFALSE
- Q10MCQ3 Marks·Choose one option

- A0
- B1
- C2
- D3
Read the passage below, then answer Q11–Q12

Based on the above data, answer the given subquestions.
Q11MCQ3 Marks·Choose one option
- A

- B

- C

- D

- A
- Q12MCQ3 Marks·Choose one option

- A

- B

- C

- D

- A
- Q13MCQ3 Marks·Choose one option

- A

- B

- C

- D

- A
Read the passage below, then answer Q14–Q15
Consider the following statements and answer the given subquestions if they are true or false.
Q14MCQ2 Marks·Choose one optionThe worst-case running time and expected running time are equal to within constant factors for any randomized algorithm.
- ATRUE
- BFALSE
- Q15MCQ2 Marks·Choose one option

- ATRUE
- BFALSE
Read the passage below, then answer Q16–Q20
Answer the given subquestions.
Q16MCQ2 Marks·Choose one optionEvery linear program has a unique optimal solution.
- ATRUE
- BFALSE
- Q17MCQ2 Marks·Choose one option

- AYes
- BNo
- Q18MCQ2 Marks·Choose one option
Consider the algorithm in the previous question no 18. Does the algorithm always output an optimal vertex cover?
- AYes
- BNo
- Q19MCQ2 Marks·Choose one option
Consider the algorithm in the previous question no 18. Does the algorithm always output a 2- approximate vertex cover?
- AYes
- BNo
- Q20MCQ2 Marks·Choose one option
Recall that the size of an optimal vertex cover is at most twice the size of a maximum matching of a graph G. Are there examples of graphs where the size of the optimal vertex cover is exactly equal to twice the size of its maximum matching? For example, this is not true for a path on three vertices: the size of both the maximum matching and minimum vertex cover is 1.
- AYes
- BNo
- Q21MCQ3 Marks·Choose one option

- A

- B

- C

- D

- A
End Term · 31 Aug 2025 (AN)End Term
- Q22MCQ3 Marks·Choose one option

- ANeither algorithm always correctly determines whether or not a given tree graph has a perfect matching.
- BBoth algorithms always correctly determine whether or not a given tree graph has a perfect matching.
- CAlgorithm B always correctly determines whether or not a given tree graph has a perfect matching; algorithm A does not.
- DAlgorithm A always correctly determines whether or not a given tree graph has a perfect matching; algorithm B does not.
Read the passage below, then answer Q23–Q27

Based on the above data, answer the given subquestions.
Q23MCQ2 Marks·Choose one option
- A3^n
- B2^n
- Cn^3
- Dn^2
- Q24MCQ2 Marks·Choose one option

- A2^n
- Bn
- C1
- D0
- Q25MCQ2 Marks·Choose one option

- A3^n
- B2^n
- C1
- D0
- Q26NAT2 Marks·Write the number
For n = 4, calculate the number of sequences of length 3 consisting only of numbers 0, 1, and 2 such that each number occurs at least once.
Your answer: - Q27NAT2 Marks·Write the number
For n = 6, calculate the number of sequences of length 5 consisting only of numbers 0, 1, and 2 such that each number occurs at least once.
Your answer: - Q28MSQ3 Marks·Choose all correct options

- AIt is in P.
- BIt is in NP.
- CIt is NP-hard.
- DIt is NP-complete.
- Q29MCQ2 Marks·Choose one option

- ATRUE
- BFALSE
- Q30MCQ3 Marks·Choose one option
Choose the correct options:
- A

- B

- C

- A
- Q31MCQ3 Marks·Choose one option

- A0
- B1
- C2
- D3
Read the passage below, then answer Q32–Q33

Based on the above data, answer the given subquestions.
Q32MCQ3 Marks·Choose one option
- A

- B

- C

- D

- A
- Q33MCQ3 Marks·Choose one option

- A

- B

- C

- D

- A
- Q34MCQ3 Marks·Choose one option

- AIn both branches of the algorithm, at least one clause is falsified.
- BIn both branches of the algorithm, at least one clause is satisfied.
- CIn both branches of the algorithm, at least two clauses are falsified.
- DIn both branches of the algorithm, at least two clauses are satisfied.
Read the passage below, then answer Q35–Q36
Consider the given statements and answer the subquestions if they are true or false.
Q35MCQ2 Marks·Choose one optionThe worst-case running time and expected running time are equal to within constant factors for any randomized algorithm.
- ATRUE
- BFALSE
- Q36MCQ2 Marks·Choose one option

- ATRUE
- BFALSE
Read the passage below, then answer Q37–Q39
Answer the given subquestions.
Q37MCQ2 Marks·Choose one optionEvery linear program has a unique optimal solution.
- ATRUE
- BFALSE
- Q38MCQ2 Marks·Choose one option

- AYes
- BNo
- Q39MCQ2 Marks·Choose one option
Recall that the size of an optimal vertex cover is at most twice the size of a maximum matching of a graph G. Are there examples of graphs where the size of the optimal vertex cover is exactly equal to twice the size of its maximum matching? For example, this is not true for a path on three vertices: the size of both the maximum matching and minimum vertex cover is 1
- AYes
- BNo
Read the passage below, then answer Q40–Q41

Based on the above data, answer the given subquestions.
Q40MCQ2 Marks·Choose one option
- AWe still get a valid solution, and the algorithm remains a 2-approximation.
- BWe still get a valid solution, and the algorithm becomes a 3-approximation.
- CWe may no longer get a valid solution.
- Q41MCQ2 Marks·Choose one option

- AWe still get a valid solution, and the algorithm remains a 2-approximation.
- BWe still get a valid solution, and the algorithm becomes a (3/2)-approximation.
- CWe may no longer get a valid solution.
- Q42MCQ3 Marks·Choose one option

- A

- B

- C

- D

- A
Quiz 2 · 3 Aug 2025 (AN)Quiz 2
Read the passage below, then answer Q43–Q54
Q43MCQ3 Marks·Choose one optionA graph G is a cluster graph if and only if it does not have an induced path on 3 vertices.
- ATRUE
- BFALSE
- Q44MCQ2 Marks·Choose one option

- A

- B

- C

- A
- Q45MCQ2 Marks·Choose one option
In the DISJOINT CLUSTER VERTEX DELETION problem, if the subgraph induced on S is not a cluster graph, we can immediately return YES.
- ATRUE
- BFALSE
- Q46MCQ2 Marks·Choose one option
In the DISJOINT CLUSTER VERTEX DELETION problem, if the subgraph induced on the vertices of S is not a cluster graph, we can immediately return NO.
- ATRUE
- BFALSE
- Q47MCQ2 Marks·Choose one option
If the subgraph induced on the vertices of S is a cluster graph and a vertex in V (G) \ S is adjacent to at least two vertices in S which are in different cliques, then we can delete it and leave the parameter unchanged.
- ATRUE
- BFALSE
- Q48MCQ2 Marks·Choose one option
If the subgraph induced on the vertices of S is a cluster graph and a vertex in V (G) \ S is adjacent to at least two vertices in S which are in different cliques, then we can delete it and decrease the parameter by 1.
- ATRUE
- BFALSE
- Q49MCQ2 Marks·Choose one option
If the subgraph induced on the vertices of S is a cluster graph and a vertex in V (G) \ S is adjacent to some but not all vertices in a clique of G[S], then we can delete it and leave the parameter unchanged.
- ATRUE
- BFALSE
- Q50MCQ2 Marks·Choose one option
If the subgraph induced on the vertices of S is a cluster graph and a vertex in V (G) \ S is adjacent to some but not all vertices in a clique of G[S], then we can delete it and decrease the parameter by 1.
- ATRUE
- BFALSE
- Q51MCQ2 Marks·Choose one option
After modifying the input instance, we can solve DISJOINT CLUSTER VERTEX DELETION by solving a matching problem on a bipartite graph.
- ATRUE
- BFALSE
- Q52MCQ2 Marks·Choose one option
DISJOINT CLUSTER VERTEX DELETION is polynomial time solvable.
- ATRUE
- BFALSE
- Q53MCQ2 Marks·Choose one option
DISJOINT CLUSTER VERTEX DELETION is NP-hard.
- ATRUE
- BFALSE
- Q54MCQ2 Marks·Choose one option

- ATRUE
- BFALSE
Read the passage below, then answer Q55–Q56

Based on the above data, answer the given subquestions.
Q55MCQ2 Marks·Choose one option
- AWe still get a valid solution, and the algorithm remains a 2-approximation.
- BWe still get a valid solution, and the algorithm becomes a 3-approximation.
- CWe may no longer get a valid solution.
- Q56MCQ2 Marks·Choose one option

- AWe still get a valid solution, and the algorithm remains a 2-approximation.
- BWe still get a valid solution, and the algorithm becomes a (3/2)-approximation.
- CWe may no longer get a valid solution.
Read the passage below, then answer Q57–Q63
In Figure 1, we have a graph G and an FVS of size 3 which is given by the box, i.e., S ∶= {a,c,e}. We need to find a DISJOINT FVS of size 2.


For each of the given statements in the subquestions, determine if it is true or false.
Q57MCQ2 Marks·Choose one optionAccording to the reduction rules for DFVS, Figure 2 shows a valid intermediate instance in the reduction with k= 2.
- ATRUE
- BFALSE
- Q58MCQ2 Marks·Choose one option
According to the reduction rules for DFVS, Figure 3 shows a valid intermediate instance in the reduction with k= 2.
- ATRUE
- BFALSE
- Q59MCQ2 Marks·Choose one option
According to the reduction rules for DFVS, Figure 4 shows a valid intermediate instance in the reduction with k= 2.
- ATRUE
- BFALSE
- Q60MCQ2 Marks·Choose one option
According to the reduction rules for DFVS, Figure 5 shows a valid intermediate instance in the reduction with k= 2.
- ATRUE
- BFALSE
- Q61MCQ2 Marks·Choose one option
According to the reduction rules for DFVS, Figure 4 shows a valid intermediate instance in the reduction with k= 1.
- ATRUE
- BFALSE
- Q62MCQ2 Marks·Choose one option
The graph in Figure 1 has a FVS disjoint from S of size 2.
- ATRUE
- BFALSE
- Q63MCQ2 Marks·Choose one option
The graph in Figure 1 has a FVS disjoint from S of size 1.
- ATRUE
- BFALSE
Read the passage below, then answer Q64–Q68

Based on the above data, answer the given subquestions.
Q64MCQ1 Mark·Choose one option
- A

- B

- C

- D

- A
- Q65MCQ1 Mark·Choose one option

- A

- B

- C

- D

- A
- Q66MCQ1 Mark·Choose one option

- A

- B

- C

- D

- A
- Q67NAT2 Marks·Write the number
For n= 4, calculate the number of sequences of length 4 consisting only of numbers 0, 1, and 2 such that each number occurs at least once.
Your answer: - Q68NAT2 Marks·Write the number
For n = 5, calculate the number of sequences of length 5 consisting only of numbers 0, 1, and 2 such that each number occurs at least once.
Your answer:
Official KeyMaster Answer Key & Explanations
Official answer keys from IIT Madras BS past papers. Click any question to review.
Reveal KeyCollapse Key
Master Answer Key & Explanations
Official answer keys from IIT Madras BS past papers. Click any question to review.