winamax.cs

T[] Concat<T>(IEnumerable<T> first, params IEnumerable<T>[] others)
{
    foreach (var other in others)
        first = first.Concat(other);
    return first.ToArray();
}

Player CreatePlayer()
{
    IEnumerable<int> ReadPlayerDeck()
    {
        var x = int.Parse(Console.ReadLine()!);
        for (var i = 0; i <= x; i++)
        {
            yield return Console.ReadLine()!.Trim('D', 'H', 'C', 'S') switch
            {
                ['J', ..] => 11,
                ['Q', ..] => 12,
                ['K', ..] => 13,
                ['A', ..] => 14,
                var card => int.Parse(card)
            };
        }
    }

    return new(ReadPlayerDeck().ToArray(), Array.Empty<int>());
}

string Round(int n, Player player1, Player player2)
{
    switch (player1.Deck, player2.Deck)
    {
        case ([], []): return "PAT";
        case (_, []): return $"1 {n}";
        case ([], _): return $"2 {n}";
        case ([var card1, ..var rest1], [var card2, ..var rest2]):
        {
            var stack1 = Concat(player1.WarStack, new[] { card1 });
            var stack2 = Concat(player2.WarStack, new[] { card2 });

            if (card1 > card2)
            {
                return Round(
                    n + 1,
                    new(Deck: Concat(rest1, stack1, stack2), WarStack: Array.Empty<int>()),
                    new(Deck: rest2, WarStack: Array.Empty<int>()));
            }

            if (card2 > card1)
            {
                return Round(
                    n + 1,
                    new(Deck: rest1, WarStack: Array.Empty<int>()),
                    new(Deck: Concat(rest2, stack1, stack2), WarStack: Array.Empty<int>()));
            }

            switch (rest1, rest2)
            {
                case ([var p11, var p12, var p13, ..var rest12], [var p21, var p22, var p23, ..var rest22]):
                {
                    if (rest12 is [] || rest22 is [])
                        return "PAT";
                    return Round(n,
                        new(Deck: rest1, WarStack: Concat(player1.WarStack, new[] { card1, p11, p12, p13 })),
                        new(Deck: rest2, WarStack: Concat(player2.WarStack, new[] { card2, p21, p22, p23 }))
                    );
                }
                    default:
                        return "PAT";
            }
        }
        default:
            return "PAT";
    }
}

Console.Write(Round(0, CreatePlayer(), CreatePlayer()));

record Player(int[] Deck, int[] WarStack);