private static ProgramPathCollection <int> Part0(string input)
{
var paths = new ProgramPathCollection <int>();
foreach (var line in input.Lines())
{
var words = line.Words().ToList();
var key = words[0].ToInt();
var cdr = words.Skip(2).Select(x => x.Trim(',')).ToInts();
paths.AddPath(key, cdr);
}
return(paths);
}
private static HashSet <int> GetGroupFor(ProgramPathCollection <int> paths, HashSet <int> seen, int key)
{
seen.Add(key);
foreach (var i in paths.GetValue(key))
{
if (seen.Contains(i))
{
continue;
}
foreach (var h in GetGroupFor(paths, seen, i))
{
seen.TryAdd(h);
}
}
return(seen);
}
private static IList <HashSet <int> > GetGroups(ProgramPathCollection <int> paths)
{
var response = new List <HashSet <int> >();
IList <int> left = new List <int>();
var seen = new HashSet <int>();
do
{
var hash = GetGroupFor(paths, new HashSet <int>(), left.FirstOrDefault());
seen.UnionWith(hash);
response.Add(hash);
left = paths.Paths.Where(x => !seen.Contains(x)).ToList();
} while (left.Count > 0);
return(response);
}
