0823.cpp

class Solution {
public:
    int numFactoredBinaryTrees(vector<int>& arr) {
        unordered_map<int,long long int>map;
      
        sort(arr.begin(),arr.end());
      
        for(int i = 0; i < size(arr); i++)
            map.insert({arr[i],1});
      
        for(int i = 1; i < size(arr); i++){
            long long int count = 0;
            
            for(int j = 0; j < i; j++)
                if(arr[i] % arr[j] == 0)
                    if(map.find(arr[i] / arr[j]) != map.end())
                        count += map.find(arr[j]) -> second * map.find(arr[i] / arr[j]) -> second;
                        
            map.find(arr[i]) -> second += count;
        }
      
        long long int sum = 0;
        
        for(auto& it : map)
            sum += it.second;
      
      return sum % 1000000007;
    }
};