CODEWITHSUNDEEP
c#
Yussra
Yussra

Reputation: 57

Find duplicate of array of Bitarray

I have array of Bitarray (each element consists of 128 bits) and I want to find the duplication of each element of it.
I've tried this code: 

  for (int i = 0; i < final.Length; i++)
            {
                final[i] = BitArrayToStr(sub_string[i]);

            }  
       var duplicates = final
      .GroupBy(s => s)
      .Where(g => g.Count() > 1)
      .Select(g => g.Key);
      var dict = new Dictionary<string,int>();
      foreach (var num in final)
      {
          if (!dict.ContainsKey(num))
          {
              dict.Add(num, 0);
          }
          dict[num]++;
      }
      bool dup=false;
      foreach (var kvp in dict)
      {
          if (kvp.Value != 1)
          {
              Console.WriteLine("{0} repeats {1} times", kvp.Key, kvp.Value);
              dup = true;

          }
      }
      if (dup == false)

      { Console.WriteLine("NO DUPLICATE"); }

      Console.WriteLine("END");


        static String BitArrayToStr(BitArray ba) //**** **** convert bit 
        array to string of chars **** 
    {
        byte[] strArr = new byte[ba.Length / 8];

        System.Text.ASCIIEncoding encoding = new System.Text.ASCIIEncoding();

        for (int i = 0; i < ba.Length / 8; i++)
        {
            for (int index = i * 8, m = 1; index < i * 8 + 8; index++, m *= 2)
            {
                strArr[i] += ba.Get(index) ? (byte)m : (byte)0;
            }
        }

        return encoding.GetString(strArr);
    }

but I don't want to convert it to string because the results will be false.
I want to know the duplication of each element of array of bitarray.
Can anyone help?

Upvotes: 0

Views: 209

Answers (1)

John Wu
John Wu

Reputation: 52240

It's pretty easy to convert a BitArray to a string of 1s and 0s:

static public string ToBitString(this BitArray This)
{
    return string.Join("", This.Cast<bool>().Select( bit => bit ? 1 : 0 ));
}

With this knowledge, we can write an EqualityComparer for BitArray, like this:

public class BitArrayComparer : IEqualityComparer<BitArray> 
{
    public bool Equals(BitArray a, BitArray b)
    {
        return a.ToBitString() == b.ToBitString();
    }

    public int GetHashCode(BitArray o)
    {
        return o.ToBitString().GetHashCode();
    }
}

If we pass the EqualityComparer to GroupBy we can now get our counts very easily:

var list = new List<BitArray>
{
    new BitArray(new bool[] { true,  true  } ),
    new BitArray(new bool[] { true,  false } ),
    new BitArray(new bool[] { true,  false } ),
    new BitArray(new bool[] { false, false } )
};

var groups = list.GroupBy( item => item, new BitArrayComparer() );

foreach (var g in groups)
{
    Console.WriteLine("Value '{0}' occurs {1} times", g.Key.ToBitString(), g.Count());
}

Output:

Value '11' occurs 1 times
Value '10' occurs 2 times
Value '00' occurs 1 times

Link to example code on DotNetFiddle

Upvotes: 0

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