p002.py

# Each new term in the Fibonacci sequence is generated by adding the previous two terms. By starting with 1 and 2, the first 10 terms will be:

# 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, ...

# By considering the terms in the Fibonacci sequence whose values do not exceed four million, find the sum of the even-valued terms.

from functools import lru_cache

@lru_cache(maxsize=None)
def fib(n: int) -> int:
    if n == 0: return n  # special case
    last: int = 0  # initially set to fib(0)
    next: int = 1  # initially set to fib(1)
    for _ in range(1, n):
        last, next = next, last + next
    return next

def fib2(n: int) -> int:
    if n < 2:  # base case
        return n
    return fib2(n - 2) + fib2(n - 1)  # recursive case

from typing import Dict
memo: Dict[int, int] = {0: 0, 1: 1}  # our base cases

def fib3(n: int) -> int:
    if n not in memo:
        memo[n] = fib3(n - 1) + fib3(n - 2)  # memoization
    return memo[n]



@lru_cache(maxsize=None)
def fib4(n: int) -> int:  # same definition as fib2()
    if n < 2:  # base case
        return n
    return fib4(n - 2) + fib4(n - 1)  # recursive case

def fib5(n: int) -> int:
    if n == 0: return n  # special case
    last: int = 0  # initially set to fib(0)
    next: int = 1  # initially set to fib(1)
    for _ in range(1, n):
        last, next = next, last + next
    return next

from typing import Generator

def fib6(n: int) -> Generator[int, None, None]:
    yield 0  # special case
    if n > 0: yield 1  # special case
    last: int = 0  # initially set to fib(0)
    next: int = 1  # initially set to fib(1)
    for _ in range(1, n):
        last, next = next, last + next
        yield next  # main generation step

if __name__ == "__main__":
    schranke = 35
    summe = 0
    for ele in range(schranke):
        fibo = fib4(ele)
        if (fibo % 2 == 0):
            summe += fibo
    
    print(summe)