# Factorial program with memoization using
# decorators.
 
# A decorator function for function 'f' passed
# as parameter
memory = {}
def memoize_factorial(f):
     
    # This inner function has access to memory
    # and 'f'
    def inner(num):
        if num not in memory:
            memory[num] = f(num)
            print('result saved in memory')
        else:
            print('returning result from saved memory')
        return memory[num]
 
    return inner
     
@memoize_factorial
def facto(num):
    if num == 1:
        return 1
    else:
        return num * facto(num-1)
 
print(facto(5))
print(facto(5)) # directly coming from saved memory