Word count exercise - 30 minutes mock interview practice - I need to work on the solution after the mock interview

WordCountExercise_30MinutesMock.cs

using System;

class Solution
{
    internal class Bucket{
      public  ListOfWords =  new List<string>; 
      
      public Bucket(
      {
        ListOfWords = new List<string>(); 
      }
    }
    
    public static string[,] WordCountEngine(string document)
    {      
      if(document == null || document.Length == 0)
      {
        return new string[0,0];
      }
      
      var processed = String.ToLower(document); 
      
      // replace 
      processed = processed.Replace('\\','\0'); 
      
      // split the words 
      var words = processed.Split(" ,!"); 
      
      // sorted the 
    }

    /// comparison sort -> nlogn -
    /// bucket sort -> detmine max value -> 1 to max buckets -> go over each word
    /// const size of bucket -> hint at most 200 
    private static string[][]  applyBucketSort(Dictionary<string, int> dict)    
    {
      // get maximum value count 
      var max = 0; 
      foreach(var pair in dict)
      {
        var number = pair.Value; 
        max = number > max ? number : max; 
      }
      // var list = new List<string> 
      var buckets = new Bucket[max]; 
      
      for(int i = 0 ; i < max; i++)
      {
        buckets[i] = new Bucket(); 
      }
      
      // continue after mock interview, 30 minutes time out      
    }
  
    private static Dictionary<string, int> storeToDict(string[] words)
    {
      var dict = new Dictionary<string, int>(); 
      
      foreach(var word in words)
      {
        if(!dict.ContainsKey(word))
        {
          dict.Add(word, 1);           
        }
        else 
        {
          dict[word]++; 
        }
      }
      
      return dict;       
    }
  
    static void Main(string[] args)
    {
    }
}

/*
constraints: lower case/ upper case -> lower case 
    delimiter at least ". !"
    sorted by descending order, number of occurrences 
    if ascending order apping to same occurrence
    replace - punctuation 'you'll'   with whitespace  ""?
      
Time complexity: linear time complexity - > 
  sorting O(nlogn)      
  counting - bucket   O(n) - number of bucket 
  
Space complexity 

*/