检查输入 if check_input(n):if n < 2:return n else:index = 2 fib_index_pre_pre = 0 fib_index_pre = 1 fib_index = 0 while n >= index:fib_index = fib_index_pre_pre + fib_index_pre fib_index_pre_pre = fib_index_pre fib_index_pre = fib_index index += 1 retu...
求斐波那契数列前20项python
根据定义递归求解，我们是根据需要求得的元素一步一步倒推，直到倒推到我们已知的元素 ( 第 0 个，第 1 个 )，属于“反向”计算，那如果“正向”计算，从已知元素递推所求元素呢？
＃递推求解，从已知元素递推所求元素
def Fib_recurrence(n):
# 检查输入
if check_input(n):
if n < 2:
return n
else:
index = 2
fib_index_pre_pre = 0
fib_index_pre = 1
fib_index = 0
while n >= index:
fib_index = fib_index_pre_pre + fib_index_pre
fib_index_pre_pre = fib_index_pre
fib_index_pre = fib_index
index += 1
return fib_index
else:
# 默认返回值
return -12021-08-10
a = b = 1
for _ in range(20):
print(a)
a,b = b,a + b2021-08-18
