GATE DA 2025 Set 1 — Question 63

NAT+2 / -0MediumRecursionFunctions, File & Error HandlingProgramming, Data Structures & Algorithms

Programming, Data Structures & Algorithms → Functions, File & Error Handling → Recursion

Last updated 5 September 2026

Question

Consider the following Python code snippet. def f(a,b): if (a==0): return b if (a%2==1): return 2*f((a-1)/2,b) return b+f(a-1,b) print(f(15,10)) The value printed by the code snippet is__________(Answer in integer)

Correct answer 160 to 160 Solution We trace the execution of f(15, 10) : 1. f(15, 10) : a = 15 (odd). Returns 2 * f((15-1)/2, 10) = 2 * f(7, 10) . 2. f(7, 10) : a = 7 (odd). Returns 2 * f((7-1)/2, 10) = 2 * f(3, 10) . 3. f(3, 10) : a = 3 (odd). Returns 2 * f((3-1)/2, 10) = 2 * f(1, 10) . 4. f(1, 10) : a = 1 (odd). Returns 2 * f((1-1)/2, 10) = 2 * f(0, 10) . 5. f(0, 10) : a = 0 . Returns b = 10. Substituting back up the chain: f(0, 10) = 10 f(1, 10) = 2 * 10 = 20 f(3, 10) = 2 * 20 = 40 f(7, 10) = 2 * 40 = 80 f(15, 10) = 2 * 80 = 160 The value printed is 160. Turn this into a strength. Explore AI-powered practice and doubt support with Success Tracker.

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Correct answer 160 to 160 Solution We trace the execution of f(15, 10) : 1. f(15, 10) : a = 15 (odd). Returns 2 * f((15-1)/2, 10) = 2 * f(7, 10) . 2. f(7, 10) : a = 7 (odd). Returns 2 * f((7-1)/2, 10) = 2 * f(3, 10) . 3. f(3, 10) : a = 3 (odd). Returns 2 * f((3-1)/2, 10) = 2 * f(1, 10) . 4. f(1, 10) : a = 1 (odd). Returns 2 * f((1-1)/2, 10) = 2 * f(0, 10) . 5. f(0, 10) : a = 0 . Returns b = 10. Substituting back up the chain: f(0, 10) = 10 f(1, 10) = 2 * 10 = 20 f(3, 10) = 2 * 20 = 40 f(7, 10) = 2 * 40 = 80 f(15, 10) = 2 * 80 = 160 The value printed is 160.

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