public override void PartOne(IInput input, IOutput output)
{
var builder = new StringBuilder();
var keypad = new Keypad(new char[, ]
{
{ '1', '2', '3' },
{ '4', '5', '6' },
{ '7', '8', '9' },
});
var position = keypad.FiveKey;
foreach (var line in input.Lines.AsMemory())
{
(var key, position) = FindKey(keypad, line.Span, position);
builder.Append(key);
}
output.WriteProperty("Code", builder.ToString());
}