def main():
n = 35 # Term to calculate
print("> A recursive approach without optimizations:")
if n < 36:
res = time_it(fib1, n)
write_result(res, n)
else:
print(
f"fib({n}): Oops! It will take so much time, so I abort it. Sorry.\n{'-'*10}"
)
print("> An iterative programming solution:")
res = time_it(fib2, n)
write_result(res, n)
print("> A dynamic programming memoized solution\n"
"for a recursive approach using a list:")
res = time_it(fib3a, n)
write_result(res, n)
print(
"> A dynamic programming memoized solution for a recursive approach\n"
"using an array of unsigned integers of 64 or 32 bits:")
res = time_it(fib3b, n)
write_result(res, n)
print("> A dynamic programming memoized solution using a dictionary:")
res = time_it(fib4, n)
write_result(res, n)
print(
"> A dynamic programming memoized solution for a recursive approach\n"
"using functools.lru_cache from the standard library:")
res = time_it(fib5, n)
write_result(res, n)
print(
"> A dynamic programming memoized solution for a recursive approach\n"
"using functools.lru_cache from the standard library.\n"
"Benchmarks function fib with the user created decorator time_it:")
res = fib6(n)
write_result(res, n)
'''Calculates the n element of the Fibonacci sequence.
The Fibonacci sequence: 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, ...
Where F(0) = 0, F(1) = 1 and F(n) = F(n - 1) + F(n - 2) for n > 1.
So, each term greater than 1 is generated by adding the previous two terms.
For example, the 6th element of the sequence is 8.
It uses a dynamic programming memoized solution for a recursive approach
using functools.lru_cache from the standard library.
Benchmarks function fib with the user created function time_it.
'''
__author__ = 'Joan A. Pinol (japinol)'
from functools import lru_cache
from fibonacci.time_it import time_it
@lru_cache(maxsize=None)
def fib(n):
if n < 2:
return n
return fib(n - 1) + fib(n - 2)
if __name__ == "__main__":
n = 35
res = time_it(fib, n)
print(f'fib({n}): {res}')