StringMerge

public class Test
{
    unsafe class Program
    {
       public static void Main(string[] args)
        {
            int t = int.Parse(Console.ReadLine());
            for (int i = 0; i < t; i++)
            {
                string[] tekst = Console.ReadLine().Split(' ');
                fixed (char* a = tekst[0])
                fixed (char* b = tekst[1])

                Console.WriteLine(Polacz(a, b));
            }
        }

        unsafe private static string Polacz(char* a, char* b )
        {
            string wynik = "";
            while (*a != 0 && *b != 0)
            {
                wynik += *a;
                wynik += *b;
                a++;
                b++;
            }
            return wynik;
        }
    }
}