所以我是python的新手，并从karatsuba乘法的伪代码中编写了这段代码，并得到某种逻辑错误
这是我使用的伪代码：
procedure karatsuba(num1, num2)
if (num1 < 10) or (num2 < 10)
return num1*num2
/* calculates the size of the numbers */
m = max(size_base10(num1), size_base10(num2))
m2 = m/2
/* split the digit sequences about the middle */
high1, low1 = split_at(num1, m2)
high2, low2 = split_at(num2, m2)
/* 3 calls made to numbers approximately half the size */
z0 = karatsuba(low1,low2)
z1 = karatsuba((low1+high1),(low2+high2))
z2 = karatsuba(high1,high2)
return (z2*10^(2*m2))+((z1-z2-z0)*10^(m2))+(z0)
以下是它的python代码：
def mul(n1,n2):
if n1<10 or n2<10:
return n1*n2
l = max(len(str(n1)),len(str(n2)))
print(l)
half = l//2
print(half)
f1 = int(str(n1)[:half])
print("f1",f1)
l1 = int(str(n1)[half:])
print("l1",l1)
f2 = int(str(n2)[:half])
print("f2",f2)
l2 = int(str(n2)[half:])
print("l2",l2)
c = mul(l1,l2)
print("c",c)
b = mul((l1+f1),(l2+f2))
print("b",b)
a = mul(f1,f2)
print("a",a)
return ((a*10^(2*half))+((b-a-c)*10^(half))+c)
var = mul(44,21)
print(var)
如果有人做过这个算法，那么有人可以建议我在哪里弄错了吗？
任何帮助都将不胜感激。