大数据算法2

test = 0

for i in range(n):

for j in range(n):

     test = test + i * j

test = 0

for i in range(n):

test = test + 1

for j in range(n):

     test = test - 1

def pow(x, n): 

    if n==0: 

       return 1 

    elif n==1: 

        return x

    elif n%2==0: 

        return pow(x*x, n//2) 

    else: 

         return pow(x*x, n//2)*x 

问它对于n的大O级别( )

def solve(f, x1, x2):

    mid = (x1 + x2) / 2

    if f(mid) == 0 or abs(x1 - x2) < 1e-8:

        return  # <A>

    elif f(mid) * f(x1) > 0:

        return # <B>

    else:

        return # <C>

如何补全该函数使其可以正常使用?