namespace Xor;

public static class Xor
{
    public static int[] Decode(int[] encoded, int first)
    {
        var arr = new int[encoded.Length + 1];
        arr[0] = first;

        for (int i = 1; i < arr.Length; i++)
        {
            first = arr[i] = encoded[i - 1] ^ first;
        }

        return arr;
    }

    public static int[] DecodeWithSpans(int[] encoded, int first)
    {
        var arr = new int[encoded.Length + 1];
        arr[0] = first;

        var encodedSpan = encoded.AsSpan();
        var arrSpan = arr.AsSpan(1);
        for (int i = 0; i < arrSpan.Length; i++)
        {
            first = arrSpan[i] = encodedSpan[i] ^ first;
        }

        return arr;
    }
}

namespace Xor;

public static class Xor
{
    public static int[] Decode(int[] encoded, int first)
    {
        var arr = new int[encoded.Length + 1];
        arr[0] = first;

        for (int i = 1; i < arr.Length; i++)
        {
            first = arr[i] = encoded[i - 1] ^ first;
        }

        return arr;
    }

    public static int[] DecodeWithSpans(int[] encoded, int first)
    {
        var arr = new int[encoded.Length + 1];
        arr[0] = first;

        var encodedSpan = encoded.AsSpan();
        var arrSpan = arr.AsSpan(1);
        for (int i = 0; i < arrSpan.Length; i++)
        {
            first = arrSpan[i] = encodedSpan[i] ^ first;
        }

        return arr;
    }
}

|          Method |     N |       Mean |    Error |   StdDev |
|---------------- |------ |-----------:|---------:|---------:|
|          Decode |  1000 |   859.4 ns |  1.70 ns |  1.59 ns |
| DecodeWithSpans |  1000 |   843.9 ns |  2.06 ns |  1.72 ns |
|          Decode | 10000 | 8,013.4 ns | 31.75 ns | 26.52 ns |
| DecodeWithSpans | 10000 | 7,857.6 ns | 13.34 ns | 10.41 ns |

|          Method |     N |       Mean |    Error |   StdDev |
|---------------- |------ |-----------:|---------:|---------:|
|          Decode |  1000 |   859.4 ns |  1.70 ns |  1.59 ns |
| DecodeWithSpans |  1000 |   843.9 ns |  2.06 ns |  1.72 ns |
|          Decode | 10000 | 8,013.4 ns | 31.75 ns | 26.52 ns |
| DecodeWithSpans | 10000 | 7,857.6 ns | 13.34 ns | 10.41 ns |

public class Solution {
    public int[] Decode(int[] encoded, int first)
    {
        var arr = new int[encoded.Length + 1];
        arr[0] = first;
        
        for (int i = 1; i < arr.Length; i++)
        {
            first = arr[i] = encoded[i-1] ^ first;
        }

        return arr;
    }
}

public class Solution {
    public int[] Decode(int[] encoded, int first)
    {
        var arr = new int[encoded.Length + 1];
        arr[0] = first;
        
        for (int i = 1; i < arr.Length; i++)
        {
            first = arr[i] = encoded[i-1] ^ first;
        }

        return arr;
    }
}