private static IEnumerable <Tile> Parse(ReadOnlyMemory <string> input)
{
foreach (var tileInput in input.Split(string.Empty))
{
var id = int.Parse(tileInput.Span[0].AsSpan().TrimStart("Tile ").TrimEnd(":"));
yield return(new Tile(id, tileInput.Slice(1).Span));
}
}
private static IEnumerable <ISet <char> > AnyoneAnswered(ReadOnlyMemory <string> input)
{
foreach (var group in input.Split(string.Empty))
{
var correctAnswers = new HashSet <char>();
foreach (var line in group)
{
correctAnswers.UnionWith(line);
}
yield return(correctAnswers);
}
}
private static IEnumerable <ISet <char> > EveryoneAnswered(ReadOnlyMemory <string> input)
{
foreach (var group in input.Split(string.Empty))
{
HashSet <char> groupAnswers = null;
foreach (var line in group)
{
groupAnswers ??= new HashSet <char>(line);
groupAnswers.IntersectWith(line);
}
yield return(groupAnswers);
}
}
private static IEnumerable <IDictionary <string, string> > ParsePassports(ReadOnlyMemory <string> input)
{
foreach (var group in input.Split(string.Empty))
{
var passport = new Dictionary <string, string>();
foreach (var line in group)
{
foreach (Match match in KeyValuePattern.Matches(line))
{
if (match.TryCapture(out var key, out var value))
{
passport.Add(key, value);
}
}
}
yield return(passport);
}
}