AorB HackerRank C sharp - study code #5 - BitArray

AorB_studyCSharp_ex5.cs

using System;
using System.Text;
using System.Collections.Generic;
using System.Collections;
using System.IO;
using System.Globalization;
class Solution {
    static void Main(String[] args)
    {
        /* Enter your code here. Read input from STDIN. Print output to STDOUT. Your class should be named Solution */
        int Q = Int32.Parse(System.Console.ReadLine());
        for (int j = 0; j < Q; j++)
        {
            int K = Int32.Parse(System.Console.ReadLine());
            BitArray A1 = ConvertHexToBitArray(System.Console.ReadLine());
            BitArray B1 = ConvertHexToBitArray(System.Console.ReadLine());
            BitArray C1 = ConvertHexToBitArray(System.Console.ReadLine());

            int m = Math.Max(Math.Max(A1.Count, B1.Count), C1.Count);
            BitArray A = new BitArray(m);
            for(int i = 0; i < A1.Count; i++)
                A[A.Count-i-1] = A1[A1.Count -i -1];
             BitArray B = new BitArray(m);
            for(int i = 0; i < B1.Count; i++)
                B[B.Count-i-1] = B1[B1.Count -i-1];
     BitArray C = new BitArray(m);
            for(int i = 0; i < C1.Count; i++)
                C[C.Count-i-1] = C1[C1.Count -i-1];
            
            for (int i = 0; i < m; i++)
            {
                if (C[i])
                {
                    if (!A[i] && !B[i])
                    {
                        B[i] = true;
                        K--;
                    }
                }
                if (!C[i])
                {
                    if (A[i])
                    {
                        A[i] = false;
                        K--;
                    }
                    if (B[i])
                    {
                        B[i] = false;
                        K--;

                    }
                }

            }
            if (K > 0)
            {
                for (int i = 0; i < m; i++)
                {

                    if (C[i])
                    {
                        if (A[i])
                        {
                            if (B[i])
                            {
                                if (K > 0)
                                {
                                    A[i] = false;
                                    K--;
                                }
                            }
                            if (!B[i])
                            {
                                if (K >= 2)
                                {
                                    A[i] = false;
                                    B[i] = true;
                                    K = K - 2;
                                }
                            }
                        }
                    }
                }

            }

            if (K < 0)
                System.Console.WriteLine(-1);
            if (K >= 0)
            {
                System.Console.WriteLine(ConvertBitArrayToHex(A));
                System.Console.WriteLine(ConvertBitArrayToHex(B));
            }
        }
    }

    public static BitArray ConvertHexToBitArray(string hexData)
    {
        if (hexData == null)
            return null; // or do something else, throw, ...

        BitArray ba = new BitArray(4 * hexData.Length);
        for (int i = 0; i < hexData.Length; i++)
        {
            int h = Int32.Parse(hexData[i].ToString(), System.Globalization.NumberStyles.HexNumber);
            for (int j = 0; j < 4; j++)
            {
                ba.Set(i * 4 + (3-j), (h & (1 << j)) != 0);
            }
        }
        return ba;
    }
   public static string ConvertBitArrayToHex(BitArray ba)
    {
    if (ba == null)
        return null; // or do something else, throw, ...

    StringBuilder s = new StringBuilder(ba.Length);
    for (int i = 0; i < ba.Length; i=i+4)
    {
        s.Append((8*Convert.ToInt32(ba[i])+4*Convert.ToInt32(ba[i+1])+2*Convert.ToInt32(ba[i+2])+1*Convert.ToInt32(ba[i+3])).ToString("X"));
    }
       string ss = s.ToString();
    ss = ss.TrimStart('0');
    if( ss == "") ss = "0";
    return ss;
    }
}