string Pipe(string input, bool part2)
{
var progs = new List <Prog>();
var inputs = input.Split('\n');
foreach (var i in inputs)
{
var id = Convert.ToInt32(i.Substring(0, i.IndexOf(' ')));
var link = i.Substring(i.IndexOf('>') + 1).Trim().Split(',').Select(x => Convert.ToInt32(x)).ToList();
var p = new Prog(id, link);
progs.Add(p);
}
var groups = 0;
bool part1 = true;
while (part2 && progs.Count > 0 || part1)
{
var linked = new List <Prog>()
{
progs[0]
};
var next = new List <int>();
next.AddRange(progs[0].Links);
while (next.Count > 0)
{
var id = next[0];
try
{
var currentProgram = progs.Where(x => x.ID == id).SingleOrDefault();
if (!linked.Contains(currentProgram))
{
linked.Add(currentProgram);
next.AddRange(currentProgram.Links);
}
next.RemoveAt(0);
if (part2)
{
progs.Remove(currentProgram);
}
}
catch
{
next.RemoveAt(0);
}
}
if (!part2)
{
groups = linked.Count;
}
else
{
groups += 1;
}
part1 = false;
}
return(groups.ToString());
}
/* Recrursively searches for the last prog node in a branch
* where the total weight doesn't match the total weight of its
* sibling nodes.
*/
private Prog FindBadWeight(Prog root)
{
if (root.Children.Count == 0)
{
return(root);
}
root.Children.Sort((a, b) => a.TotalWeight - b.TotalWeight);
Prog badChild = null;
if (root.Children[0].TotalWeight != root.Children[1].TotalWeight)
{
badChild = root.Children[0];
}
else if (root.Children[^ 1].TotalWeight != root.Children[^ 2].TotalWeight)
public override object Task2()
{
Prog root = FillTree(rootName, null);
Prog badProg = FindBadWeight(root);
foreach (Prog p in badProg.Parent.Children)
{
if (p == badProg)
{
continue;
}
int weightDelta = badProg.TotalWeight - p.TotalWeight;
return(badProg.Weight - weightDelta);
}
return(null);
}