Count distinct prime factors for each element of an array

using System;

class Program
{
    // A function to provide the count of distinct prime factors of a given number
    static int PrimeFactors(int n)
    {
        // To store the count of distinct prime factors of the given number
        int count = 0;
        
        // Boolean variable to check if an element is included in its prime factors or not
        bool val = false;
        
        // Remove all 2s that can be prime factors of n
        while (n % 2 == 0)
        {
            val = true;
            n = n / 2;
        }
        
        // If 2 is included
        if (val)
        {
            count++;
        }

        // n must be odd at this point, so we can skip one element (Note i = i + 2)
        for (int i = 3; i <= Math.Sqrt(n); i += 2)
        {
            // To check whether i is included in prime factors
            val = false;
            
            // While i divides n, divide n
            while (n % i == 0)
            {
                val = true;
                n = n / i;
            }
            
            // If i is included in prime factors
            if (val)
            {
                count++;
            }
        }

        // This condition is to handle the case when n is a prime number greater than 2
        if (n > 2)
        {
            count++;
        }
        
        return count;
    }

    // Function to get the distinct factor count of an array
    static void GetFactorCount(int[] arr)
    {
        // Traverse every array element
        foreach (int num in arr)
        {
            Console.Write(PrimeFactors(num) + " ");
        }
    }

    static void Main()
    {
        int[] arr = { 6, 9, 12 };
        GetFactorCount(arr);
    }
}

// C# program for the above approach
using System;
using System.Collections.Generic;

class GFG 
{

  static int MAX = 100001;

  // Stores smallest prime
  // factor for every number
  static int[] spf;

  // Stores distinct prime factors
  static List<List<int>> v;

  // Function to find the smallest
  // prime factor of every number
  static void sieve()
  {

    // Mark the smallest prime factor
    // of every number to itself
    for (int i = 1; i < MAX; i++)
      spf[i] = i;

    // Separately mark all the
    // smallest prime factor of
    // every even number to be 2
    for (int i = 4; i < MAX; i = i + 2)
      spf[i] = 2;
    for (int i = 3; i * i < MAX; i++)

      // If i is prime
      if (spf[i] == i) {

        // Mark spf for all numbers
        // divisible by i
        for (int j = i * i; j < MAX; j = j + i) {

          // Mark spf[j] if it is
          // not previously marked
          if (spf[j] == j)
            spf[j] = i;
        }
      }
  }

  // Function to find the distinct
  // prime factors
  static void DistPrime()
  {
    for (int i = 1; i < MAX; i++) {

      int idx = 1;
      int x = i;

      // Push all distinct of x
      // prime factor in v[x]
      if (x != 1)
        v[i].Add(spf[x]);

      x = x / spf[x];

      while (x != 1) {

        if (v[i][idx - 1] != spf[x]) {

          // Pushback into v[i]
          v[i].Add(spf[x]);

          // Increment the idx
          idx += 1;
        }

        // Update x = (x / spf[x])
        x = x / spf[x];
      }
    }
  }

  // Function to get the distinct
  // factor count of arr[]
  static void getFactorCount(int[] arr, int N)
  {

    // initialization
    spf = new int[MAX];
    v = new List<List<int>>() ;
    for (int i = 0; i < MAX; i++)
      v.Add(new List<int>());

    // Precompute the smallest
    // Prime Factors
    sieve();

    // For distinct prime factors
    // Fill the v[] vector
    DistPrime();

    // Count of Distinct Prime
    // Factors of each array element
    for (int i = 0; i < N; i++) {
      Console.Write((int)v[arr[i]].Count + " ");
    }
  }

  // Driver Code
  public static void Main(string[] args)
  {

    int[] arr = { 6, 9, 12 };
    int N = arr.Length;

    getFactorCount(arr, N);
  }
}

// This code is contributed by phasing17.