using System;

​

public static class Program

{   

    public static void Main()

    {

        TestHCA();

        Console.WriteLine();

        TestAOT();

    }

    private static void TestHCA()

    {

        Console.WriteLine("HCA:");

        for(int ownshipTrueHeading = 0; ownshipTrueHeading <= 360; ownshipTrueHeading += 45)

        {

            for(int othershipTrueHeading = 0; othershipTrueHeading <= 360; othershipTrueHeading += 45)

            {

                double hca = HCA(ownshipTrueHeading, othershipTrueHeading);

                Console.WriteLine($"{ownshipTrueHeading} => {othershipTrueHeading} = {hca}");

            }

        }

    }

    private static void TestAOT()

    {

        Console.WriteLine("AOT:");

        for(int ownshipTrueHeading = 0; ownshipTrueHeading <= 360; ownshipTrueHeading += 45)

        {

            for(int bearingToOthership = 0; bearingToOthership <= 360; bearingToOthership += 45)

            {

                double aot = AOT(ownshipTrueHeading, bearingToOthership);

                Console.WriteLine($"{ownshipTrueHeading} => {bearingToOthership} => {aot}");

            }

        }

    }

    // from heading: 

    private static double HCA(double ownshipTrueHeading, double othershipTrueHeading)

    {

        ownshipTrueHeading = NormalizeHeading(ownshipTrueHeading);

        othershipTrueHeading = NormalizeHeading(othershipTrueHeading);

        double hca = TurnTowards(ownshipTrueHeading, othershipTrueHeading);

        return Math.Abs(hca);

    }

​

    private static double AOT(double ownshipTrueHeading, double bearingToOthership)

    {

        ownshipTrueHeading = NormalizeHeading(ownshipTrueHeading);

        bearingToOthership = NormalizeHeading(bearingToOthership);

        double recipOwnshipHeading = ReciprocalHeading(ownshipTrueHeading);

        double aot = TurnTowards(from: recipOwnshipHeading, to: bearingToOthership);

        return aot;

    }

    // + => right

    // - => left

    private static double TurnTowards(double from, double to)

    {

        from %= 360;

        to %= 360;

​

        double diff = to - from;

        int sign = Math.Sign(diff);

        double absDiff = Math.Abs(diff);

​

        if (absDiff > 180)

        {

            absDiff = 360 - absDiff;

            sign = -sign;

        }

​

        return sign * absDiff;

    }

​

    // forces 0-360

    private static double NormalizeHeading(double heading)

    {

        heading %= 360;

        if (heading < 0)

            heading += 360;

        return heading;

    }

    private static double ReciprocalHeading(double heading)

        => (heading + 180) % 360;

}