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

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<pre>
<strong>Input:</strong> nums = [21,4,7]
<strong>Output:</strong> 32
<strong>Explanation:</strong> 
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.
</pre>

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> nums = [21,21]
<strong>Output:</strong> 64
</pre>

<p><strong class="example">Example 3:</strong></p>

<pre>
<strong>Input:</strong> nums = [1,2,3,4,5]
<strong>Output:</strong> 0
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>1 &lt;= nums.length &lt;= 10<sup>4</sup></code></li>
	<li><code>1 &lt;= nums[i] &lt;= 10<sup>5</sup></code></li>
</ul>

class Solution {
public:
    int sumFourDivisors(vector<int>& nums) {
        const int MaxN = 1e5 + 2;

        vector<bool> isPrime(MaxN, true);
        isPrime[0] = isPrime[1] = false;
        vector<long long int> primes;
        for(int i = 2; i < MaxN; i++){
            if(!isPrime[i]) continue;
            primes.push_back(i);
            for(int j = 2 * i; j < MaxN; j+=i) isPrime[j] = false;
        }

        int sum = 0;

        for(auto num: nums){
            for(auto prime: primes){
                if(num % prime == 0){
                    if(num == prime * prime * prime){
                        sum += 1 + prime + prime * prime + prime * prime * prime;
                        break;
                    }else if(isPrime[num / prime] && prime != num / prime){
                        sum += 1 + prime + num / prime + num;
                        break;
                    }
                }
            }
        }

        return sum;
    }
};
20200