Consider the following recurrence relation: T(n) = √(n) T(√(n)) + n & for n ≥ 1, 1 & for n = 1. Which one of the following options is CORRECT?
Topic-wise GATE CS PYQs with verified steps
GATE CSE 2024 Set 1 · Q42
Time
Select one answerSingle correct
Solution
Official answer: A) T(n) = (n log log n)
Asymptotic AnalysisGiven the recurrence relation for :
Divide both sides by :
Define . The recurrence simplifies to:
To solve this, let , so and :
Let $G(m) = S(2^m)$. Then:
By the Master Theorem (Case 2 with ):
Substitute back :
Since :
Hence, (A) is the correct option.
Try the question first, then check your work.
Examiner trap
Divide both sides of the recurrence relation by and substitute , then apply the change of variables .
This Asymptotic Analysis previous year question is Q42 of the GATE CSE 2024 Set 1 paper. Find more GATE CSE PYQs on Asymptotic Analysis in Algorithms, or browse all GATE CSE PYQs.
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Asymptotic Analysis has 31 GATE CSE PYQs across 19 papers from 2011 to 2026. 12 of them are 2-mark MCQs like this one, and GATE CSE 2024 Set 1 has 2.
How GATE tests Asymptotic AnalysisIndependent practice explanation verified by the GateAI team. GATE is conducted by the IITs; question text follows the official paper.