Consider the following ANSI C program.

The output of the program upon execution is \(\underline{\hspace{2cm}}\).

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 160 (Answer in integer).

Answer 1

To solve the problem, we need to calculate the output of the function foo(int x, int y, int q) when called with the parameters foo(15, 15, 10).

The function implements a recursive structure. Let's break down its logic:

Now, let's compute foo(15, 15, 10):

Start with foo(15, 15, 10). Neither condition x <= 0 nor y <= 0 are satisfied, so execute: foo(15, 5, 10) + foo(5, 15, 10).
Calculate foo(15, 5, 10):
- Reduce to: foo(15, -5, 10) + foo(5, 5, 10).
- Calculate foo(15, -5, 10): y <= 0, thus foo(5, -5, 10).
- Calculate foo(5, -5, 10): y <= 0, thus foo(-5, -5, 10).
  - foo(-5, -5, 10): return 10.
- Calculate foo(5, 5, 10): foo(5, -5, 10) + foo(-5, 5, 10).
- Already calculated foo(5, -5, 10) = 10.
- Calculate foo(-5, 5, 10): x <= 0, thus foo(-5, -5, 10).
- Already calculated foo(-5, -5, 10) = 10.
- Return 10 + 10 = 20 for foo(5, 5, 10).
- Return 10 + 20 = 30 for foo(15, 5, 10).
Now calculate foo(5, 15, 10):
- Reduce to: foo(5, 5, 10) + foo(-5, 15, 10).
- Already calculated foo(5, 5, 10) = 20.
- Calculate foo(-5, 15, 10): x <= 0, thus foo(-5, 5, 10).
- Already calculated foo(-5, 5, 10) = 10.
- Return 20 + 10 = 30 for foo(5, 15, 10).
Finally, return 30 + 30 = 60 for foo(15, 15, 10).

The output of the program is 60, which falls within the given range of 60, 60.

Show Hint