###################################################
# 01 基础实现 （递归）
def fibonacci_01(num):
if num == 1:
return 1
if num == 2:
return 1
if num > 2:
return fibonacci_01(num - 1) + fibonacci_01(num - 2)
###################################################
# 02 通过字典进行缓存加速 （递归）
fibonacci_cache = {}
def fibonacci_02(num):
if num in fibonacci_cache:
return fibonacci_cache[num]
if num == 1:
result = 1
if num == 2:
result = 1
if num > 2:
result = fibonacci_02(num - 1) + fibonacci_02(num - 2)
fibonacci_cache[num] = result
return result
###################################################
# 03 值判定，通过lru_cache实现缓存加速 （递归）
from functools import lru_cache
@lru_cache(maxsize=1000)
def fibonacci_03(num):
if type(num) != int or num <= 0:
raise TypeError("num must have a type int and num not is 0 and negative")
if num == 1 or num == 2:
return 1
if num > 2:
return fibonacci_03(num - 1) + fibonacci_03(num - 2)
###################################################
# 04 通过yield实现 （生成器）
def fibonacci_04(num):
a, f, n = 0, 1, 0
while n < num:
yield f
a, f = f, a + f
n += 1
###################################################
# 05 迭代器实现斐波那契数列 （迭代器）
class Fibonacci_05(object):
def __init__(self, num):
self.num = num
self.counter = 0
self.a = 0
self.f = 1
def __iter__(self):
return self
def __next__(self):
if self.counter <= self.num:
result = self.f
self.a, self.f = self.f, self.f + self.a
self.counter += 1
return result
else:
raise StopIteration
###################################################
# 06
if __name__ == '__main__':
fib = Fibonacci_05(10)
for i in fib:
print(i)
# fff = fibonacci_02(10)
# print(fff)
# print(fibonacci_cache)
# fff = fibonacci_04(5)
# for i in fibonacci_04(5):
# print(i)
# print(fff)
