count pairs

class Solution {
public:
    // Time Complexity:- O(N^2)
    // Space Complexity:- O(1)
    int countPairs(vector<int>& nums, int k) {
       int n = nums.size(),count_of_pairs = 0;
       for(int i=0;i<n;i++){
           for(int j = i + 1;j<n;j++){
               if(nums[i]==nums[j]){
                   int product = i * j;
                   if(product%k==0){
                       count_of_pairs++;
                   }
               }
           }
       }
       return count_of_pairs;
    }
};