python直观解法

解题思路:

注意事项:

参考代码:

cow_age = [1, 0, 0]
n = int(input())

for year in range(2, n+1):
   temp = cow_age[2]
   cow_age[2] += cow_age[1]
   cow_age[1] = cow_age[0]
   cow_age[0] = temp

print(sum(cow_age))