Amicable numbers

https://projecteuler.net/problem=21

Amicable numbers

Problem 21

Let d(n) be defined as the sum of proper divisors of n (numbers less than n which divide evenly into n).

If d(a) = b and d(b) = a, where a ≠ b, then a and b are an amicable pair and each of a and b are called amicable numbers.

For example, the proper divisors of 220 are 1, 2, 4, 5, 10, 11, 20, 22, 44, 55 and 110; therefore d(220) = 284. The proper divisors of 284 are 1, 2, 4, 71 and 142; so d(284) = 220.

Evaluate the sum of all the amicable numbers under 10000.

def sumAmicable():
result = 0
#保存已经计算的数据
ddict = {}
for i in range(2,10000):
if i not in ddict:
ddict[i] = d(i)
#对应的值小于i的时候，就不算了，因为我们是从小到大计算过来的
if ddict[i] > i:
if ddict[i] not in ddict:
ddict[ddict[i]] = d(ddict[i])
if ddict[ddict[i]] == i:
result += (ddict[i] + i)
return result

import math
def d(n):
factor = [1]
temp = int(math.sqrt(n))
for i in range(2,temp +1):
if n % i == 0:
factor.append(i)
factor.append(n/i)
if temp ** 2 == n:
return sum(factor) - temp
return sum(factor)

print(sumAmicable())