Day02Task2.cs

namespace AdventOfCode2021;
public class Day02Task2
{
    public Day02Task2()
    {
        moveFuncByCommand = new Dictionary<string, Func<int, PositionWithAim, PositionWithAim>>
        {
            ["forward"] = (commandValue, position) => position with { 
                Horizontal = position.Horizontal + commandValue, 
                Depth = position.Depth + (position.Aim * commandValue) 
            },
            ["down"] = (commandValue, position) => position with { Aim = position.Aim + commandValue },
            ["up"] = (commandValue, position) => position with { Aim = position.Aim - commandValue },
        };
    }

    protected readonly Dictionary<string, Func<int, PositionWithAim, PositionWithAim>> moveFuncByCommand;

    public Position MoveSubmarine(string[] commands)
    {
        var result = new PositionWithAim(0, 0, 0);
        foreach (var cmd in commands) 
        {
            var nameAndValue = cmd.Split(" ", StringSplitOptions.TrimEntries);
            result = moveFuncByCommand[nameAndValue[0]].Invoke(int.Parse(nameAndValue[1]), result);
        }
        return result;
    }
}

public record PositionWithAim(int Horizontal, int Depth, int Aim) : Position(Horizontal, Depth)
{
}