阿里2020.7.31笔试

示例：3头牛，2种颜色

选 0 头牛    1种

选 1 头牛    3x2 种

选 2 头牛    3x2^2 种

选 3 头牛    1x2^3 种

共27种

def result(n,c):

    if n>=1 and n<=10\*\*9 and c>=1 and c<=10\*\*9:

        sum = 0



        for i in range(n+1):

            fenm = 1

            fenz = 1

            if i == 0:

                sum =sum + 1

                continue

            for j in range(i):

                fenm = fenm\*(n-j)

                fenz = fenz\*(1+j)

            C = int(fenm/fenz)

            M = c\*\*i

            sum += C \* M

    return(sum%(10\*\*9))



if \_\_name\_\_ =='\_\_main\_\_':

#    n,c=map(int,input().split())

#   print(result(n,c))

    print(result(3,2))