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62 lines (46 loc) · 1.5 KB
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"""
This module contains various recursive functions including:
- A naive Fibonacci implementation
- A tail-recursive Fibonacci implementation
- A function to recursively find an element in an array
"""
def fib(n):
"""Naive Fibonacci implementation"""
if n <= 1:
return n
return fib(n - 2) + fib(n - 1)
def fib_tail(n):
"""Tail-recursive Fibonacci implementation"""
return fib_tail_helper(n, 1, 1)
def fib_tail_helper(n, f2, f1):
"""Helper function for tail-recursive Fibonacci implementation"""
if n <= 2:
return f1
return fib_tail_helper(n - 1, f1, f1 + f2)
def find_in_array(arr, target):
"""Recursively find an element in an array"""
if not arr:
return False
if target == arr[0]:
return True
return find_in_array(arr[1:], target)
def main():
"""Main function"""
k = [-2, 0, 2, 4, 6, 8, 10, 9, 7, 5, 3, 1, -1, -3]
print()
print("Testing fib:")
for value in range(10):
print(f" fib({value})={fib(value)}")
print()
print("Testing fib_tail:")
for value in [1, 2, 3, 4, 5, 7, 10, 20, 50, 100]:
print(f" fib_tail({value})={fib_tail(value)}")
print()
print("Testing search_value:")
for search_value in [3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, -4]:
if find_in_array(k, search_value):
print(f" {search_value} is found in array")
else:
print(f" {search_value} NOT found in array")
if __name__ == "__main__":
main()