Kth Smallest Prime Fraction Leetcode Solution

// Declaration of a class named Solution
class Solution 
{ 
  // Access specifier: public members are accessible from outside the class
 public: 
  // Declaration of a function kthSmallestPrimeFraction which takes a vector of integers and an integer as input arguments
  vector<int> kthSmallestPrimeFraction(vector<int>& arr, int k) 
  { 
    // Declaration of a constant integer n and assigning it the size of the input vector arr
    const int n = arr.size(); 
    // Declaration and initialization of a double variable l with value 0.0
    double l = 0.0; 
    // Declaration and initialization of a double variable r with value 1.0
    double r = 1.0; 

    // Loop until l is less than r
    while (l < r) 
    { 
      // Declaration and initialization of a double variable m as the midpoint between l and r
      const double m = (l + r) / 2.0; 
      // Declaration and initialization of an integer variable fractionsNoGreaterThanM with value 0
      int fractionsNoGreaterThanM = 0; 
      // Declaration and initialization of an integer variable p with value 0
      int p = 0; 
      // Declaration and initialization of an integer variable q with value 1
      int q = 1; 

      // For each index i, find the first index j such that arr[i] / arr[j] <= m,
      // so fractionsNoGreaterThanM for index i will be n - j.
      // Loop through each index i from 0 to n-1
      for (int i = 0, j = 1; i < n; ++i) 
      { 
        // Find the first index j such that arr[i] / arr[j] <= m
        while (j < n && arr[i] > m * arr[j]) 
        // Increment j
          ++j; 
        // If j reaches the end of the array
        if (j == n) 
        // Exit the loop
          break; 
        fractionsNoGreaterThanM += n - j; // Increment fractionsNoGreaterThanM by n - j
        if (p * arr[j] < q * arr[i]) { // If the current fraction is smaller than the previous one
          p = arr[i]; // Update p
          q = arr[j]; // Update q
        }
      }

      // If fractionsNoGreaterThanM is equal to k
      if (fractionsNoGreaterThanM == k) 
      // Return the fraction p/q
        return {p, q}; 
      // If fractionsNoGreaterThanM is greater than k
      if (fractionsNoGreaterThanM > k) 
         // Update r
        r = m;
      // If fractionsNoGreaterThanM is less than k
      else 
      // Update l
        l = m; 
    }

    // Throw an exception if the loop exits without finding the kth smallest prime fraction
    throw; 
  }
};