Indian Institute of Technology Madras
BS Degree Programme · Examination & Study Paper
Advanced Algorithms
Greedy algorithms & their pitfalls
Examination Instructions & Guidelines
- Solve on notebook/paper first before checking solutions.
- MCQ: Exactly 1 option is correct. Negative marking applies.
- 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–Q5
Answer the given subquestions.
Q2MCQ2 Marks·Choose one option
- AYes
- BNo
- Q3MCQ2 Marks·Choose one option
Consider the algorithm in the previous question no 18. Does the algorithm always output an optimal vertex cover?
- AYes
- BNo
- Q4MCQ2 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
- Q5MCQ2 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
End Term · 31 Aug 2025 (AN)End Term
- Q6MCQ3 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 Q7–Q8
Answer the given subquestions.
Q7MCQ2 Marks·Choose one option
- AYes
- BNo
- Q8MCQ2 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