309
Объяснение:
F(1) = 1
F(2) = 3
F(n) = F(n – 1) * n + F(n – 2) * (n – 1) при n > 2
Немного посчитаем подставляя значения n и предыдущих F(n)
n = 3 F(1) = 1 F(2) = 3
F(3) = F(3 – 1) * 3 + F(3 – 2) * (3 – 1) = F(2) * 3 + F(1) * 2 = 3 * 3 + 1 * 2 = 9 + 2 = 11
n = 4 F(2) = 3 F(3) = 11
F(4) = F(4 – 1) * 4 + F(4 – 2) * (4 – 1) = F(3) * 4 + F(2) * 3 = 11 * 4 + 3 * 3 = 44 + 9 = 53
n = 5 F(3) = 11 F(4) = 53
F(5) = F(5 – 1) * 5 + F(5 – 2) * (5 – 1) = F(4) * 5 + F(3) * 4 = 53 * 5 + 11 * 4 = 265 + 44 = 309
def rate_f(movies):
if len(dictionary[movies]) == 0:
return True
def film_in_dictionary(movies):
if movies in dictionary:
return True
else:
return False
def average(movies):
mean = 0
for key2 in dictionary[movies].keys():
mean += dictionary[movies][key2]
print(f'{movies} средняя оценка: {mean / len(dictionary[movies])}')
dictionary = {}
while True:
command = input('Введите команду: ')
if command != 'exit' and command != 'list' and command != 'add' and command != \
'delete' and command != 'rate' and command != 'find':
print('Error')
continue
if command == 'exit':
break
if command == 'list':
for key in dictionary.keys():
if rate_f(key):
print(f'{key} не оценивался')
else:
average(key)
continue
film = input('Введите название фильма: ')
if command == 'add':
if film_in_dictionary(film):
print('Error')
else:
dictionary[film] = {}
elif command == 'delete':
if film in dictionary:
del dictionary[film]
else:
print('Error')
elif command == 'rate':
name = input('Имя пользователя: ')
rate = float(input('Оценка: '))
if 0 < rate <= 10:
dictionary[film][name] = rate
else:
print('Error')
elif command == 'find':
if rate_f(film):
continue
for name, rate in dictionary[film].items():
print(f'{name} поставил оценку: {rate}')
average(film)
