using System;

using System.Linq;              

​

public class Program

{

    const int KANJI_START = 0x4e00;

    const int KANJI_END = 0x9faf;

​

    static bool ConstainsKanji(string fullName)

    {

        fullName = fullName?.Trim();

​

        if (!fullName?.All(x => x >= KANJI_START && x <= KANJI_END) ?? false)

            return false;

        return true;

    }

    public static void Main()

    {

        Console.WriteLine(ConstainsKanji("Hello World"));

        Console.WriteLine(ConstainsKanji("和晃 川口"));

        Console.WriteLine(ConstainsKanji("和晃川口"));

        Console.WriteLine(ConstainsKanji(null));

        Console.WriteLine(ConstainsKanji(""));

    }

}