<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 calci(int num1,int num2){
        int terms = (pow(num1,num2+1)-1)/(num1-1);
        return terms;
    }
    int countOfDiv(int n){
        // vector<pair<int,int>>p;
        unordered_map<int,int> mp;
        int copy = n;
        for(int i=2;i*i<=copy;i++){
            if(n%i==0){
                int cnt = 0;
                while(n%i==0){
                    mp[i]++;
                    n/=i;
                }
                // p.push_back({i,cnt});
            }
        }
        if(n>1)    mp[n]++;
        

       
        int product = 1;
        for(auto &val: mp) product *= (val.second+1);
        if(product==4){
            int ans = 1;
            for(auto &val: mp) ans = ans*(calci(val.first,val.second));
            return ans;
        }
        else return 0;
    }
    int sumFourDivisors(vector<int>& nums) {
        int res = 0;
        for(int i=0;i<nums.size();i++)  res += countOfDiv(nums[i]);
        return res;
    }
};
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