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1390. Four Divisors

Difficulty Topics

Description

Given an integer array nums, return the sum of divisors of the integers in that array that have exactly four divisors. If there is no such integer in the array, return 0.

 

Example 1:

Input: nums = [21,4,7]
Output: 32
Explanation: 
21 has 4 divisors: 1, 3, 7, 21
4 has 3 divisors: 1, 2, 4
7 has 2 divisors: 1, 7
The answer is the sum of divisors of 21 only.

Example 2:

Input: nums = [21,21]
Output: 64

Example 3:

Input: nums = [1,2,3,4,5]
Output: 0

 

Constraints:

  • 1 <= nums.length <= 104
  • 1 <= nums[i] <= 105

Solution

four-divisors.py
class Solution:
    def sumFourDivisors(self, nums: List[int]) -> int:
        res = 0

        for num in nums:
            s = set()
            for i in range(1, floor(sqrt(num)) + 1):

                if num % i == 0:
                    s.add(num//i)
                    s.add(i)

                if len(s) > 4:
                    break

            if len(s) == 4:
                res += sum(s)

        return res