public static void Run(string[] input)
{
D7Graph g = new D7Graph(input);
string root = part01(g);
Console.WriteLine("Part 1: " + root);
Console.WriteLine(get_unbalanced(g, g.children("ugml")));
}
static bool children_unbalanced(D7Graph g, string root)
{
HashSet <int> ws = new HashSet <int>();
foreach (string c in g.children(root))
{
ws.Add(g.weight(c));
}
return(ws.Count > 1);
}
static string part01(D7Graph g)
{
foreach (string n in g.nodes.Keys)
{
if (g.reachable(n) == g.nodes.Count)
{
return(n);
}
}
return("??");
}
static int part02(D7Graph g, string root)
{
bool found = false;
while (!found)
{
string[] targets = g.children(root);
string unbalanced = get_unbalanced(g, targets);
if (unbalanced == null)
{
found = true;
}
else
{
root = unbalanced;
}
}
}
static string get_unbalanced(D7Graph g, string[] cs)
{
var q = cs.GroupBy(
str => g.weight(str),
str => str,
(w, n) => new
{
Key = w,
Count = n.Count(),
Res = n.Min()
});
foreach (var res in q)
{
if (res.Count == 1)
{
return(res.Res);
}
}
return(null);
}