Day2.cs

var path = @"D:\code\decriptor\input2.txt";

var lost = 0;
var draw = 3;
var won = 6;

var rock = 1; // A, X
var paper = 2; // B, Y
var scissors = 3; // C, Z

var input = File.ReadLines(path);
//var input = new[] { "A Y", "B X", "C Z" };

// Part 1
var totalScore = 0;
foreach (var round in input)
{
	var player1 = round[0];
	var player2 = round[round.Length - 1];

	var part1 = player2 switch
	{
		'X' => rock,
		'Y' => paper,
		'Z' => scissors
	};
	
	var part2 = (player1, player2) switch
	{
		('A', 'X') => draw,
		('A', 'Y') => won,
		('A', 'Z') => lost,

		('B', 'X') => lost,
		('B', 'Y') => draw,
		('B', 'Z') => won,

		('C', 'X') => won,
		('C', 'Y') => lost,
		('C', 'Z') => draw
	};
	
	totalScore += part1 + part2;
}

totalScore.Dump();


// Part 2
var totalScorePart2 = 0;
foreach (var round in input)
{
	var player1 = round[0];
	var player2 = round[round.Length - 1];

	var part1 = player2 switch
	{
		'X' => lost,
		'Y' => draw,
		'Z' => won
	};

	var part2 = (player1, player2) switch
	{
		('A', 'X') => scissors,
		('A', 'Y') => rock,
		('A', 'Z') => paper,

		('B', 'X') => rock,
		('B', 'Y') => paper,
		('B', 'Z') => scissors,

		('C', 'X') => paper,
		('C', 'Y') => scissors,
		('C', 'Z') => rock
	};

	totalScorePart2 += part1 + part2;
}

totalScorePart2.Dump();