Indian Institute of Technology Madras
BS Degree Programme · Examination & Study Paper
Advanced Algorithms
Quiz 2 · 3 Aug 2025 (Afternoon)
Examination Instructions & Guidelines
- Solve on notebook/paper first before checking solutions.
- MCQ: Exactly 1 option is correct. Negative marking applies.
- NAT: Numerical response. No negative marking.
- Scientific calculator allowed for all calculations.
- Official answer key is sealed at the end of this sheet.
Read the passage below, then answer Q1–Q12
Q1MCQ3 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
- Q2MCQ2 Marks·Choose one option

- A

- B

- C

- A
- Q3MCQ2 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
- Q4MCQ2 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
- Q5MCQ2 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
- Q6MCQ2 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
- Q7MCQ2 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
- Q8MCQ2 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
- Q9MCQ2 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
- Q10MCQ2 Marks·Choose one option
DISJOINT CLUSTER VERTEX DELETION is polynomial time solvable.
- ATRUE
- BFALSE
- Q11MCQ2 Marks·Choose one option
DISJOINT CLUSTER VERTEX DELETION is NP-hard.
- ATRUE
- BFALSE
- Q12MCQ2 Marks·Choose one option

- ATRUE
- BFALSE
Read the passage below, then answer Q13–Q14

Based on the above data, answer the given subquestions.
Q13MCQ2 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.
- Q14MCQ2 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 Q15–Q21
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.
Q15MCQ2 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
- Q16MCQ2 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
- Q17MCQ2 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
- Q18MCQ2 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
- Q19MCQ2 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
- Q20MCQ2 Marks·Choose one option
The graph in Figure 1 has a FVS disjoint from S of size 2.
- ATRUE
- BFALSE
- Q21MCQ2 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 Q22–Q26

Based on the above data, answer the given subquestions.
Q22MCQ1 Mark·Choose one option
- A

- B

- C

- D

- A
- Q23MCQ1 Mark·Choose one option

- A

- B

- C

- D

- A
- Q24MCQ1 Mark·Choose one option

- A

- B

- C

- D

- A
- Q25NAT2 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: - Q26NAT2 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: