public static void PartOne()
{
string input = InputHelper.GetInputFromFile("6");
IEnumerable <(string Orbitee, string Orbiter)> orbits = input.Split("\r\n").Select(line => { var parts = line.Split(")"); return(parts[0], parts[1]); });
OrbitTree tree = new OrbitTree();
Queue <Orbitable> orbitablesToProcess = new Queue <Orbitable>();
orbitablesToProcess.Enqueue(tree.CenterOfMass);
while (orbitablesToProcess.Count() > 0)
{
Orbitable currentOrbitable = orbitablesToProcess.Dequeue();
var orbiters = orbits.Where(o => o.Orbitee == currentOrbitable.Code).Select(o => o.Orbiter);
foreach (string orbiterCode in orbiters)
{
Orbitable orbitable = new Orbitable(orbiterCode, currentOrbitable);
currentOrbitable.Orbiters.Add(orbitable);
orbitablesToProcess.Enqueue(orbitable);
}
}
//Display(tree.CenterOfMass);
Console.WriteLine($"Weight : {Weight(tree.CenterOfMass)}");
}
private static int DistanceDownTo(Orbitable link, Orbitable santa, int depth = 0)
{
if (link.Orbiters.Contains(santa))
{
return(depth);
}
Orbitable nextLink = link.Orbiters.First(o => Flatten(o).Contains(santa));
return(DistanceDownTo(nextLink, santa, depth + 1));
}
private static IEnumerable <Orbitable> Flatten(Orbitable e)
{
yield return(e);
foreach (Orbitable orbitable in e.Orbiters)
{
foreach (Orbitable flat in Flatten(orbitable))
{
yield return(flat);
}
}
}
private static int GetDistanceBetween(OrbitTree tree, Orbitable me, Orbitable santa)
{
int distanceUp = 0;
Orbitable link = me.Orbitee;
IEnumerable <Orbitable> reachables = Flatten(link);
while (!reachables.Contains(santa))
{
link = link.Orbitee;
reachables = Flatten(link);
distanceUp++;
}
return(distanceUp + DistanceDownTo(link, santa));
}
public static void PartTwo()
{
string input = InputHelper.GetInputFromFile("6");
IEnumerable <(string Orbitee, string Orbiter)> orbits = input.Split("\r\n").Select(line => { var parts = line.Split(")"); return(parts[0], parts[1]); });
OrbitTree tree = new OrbitTree();
Queue <Orbitable> orbitablesToProcess = new Queue <Orbitable>();
orbitablesToProcess.Enqueue(tree.CenterOfMass);
Orbitable me = null, santa = null;
while (orbitablesToProcess.Count() > 0)
{
Orbitable currentOrbitable = orbitablesToProcess.Dequeue();
var orbiters = orbits.Where(o => o.Orbitee == currentOrbitable.Code).Select(o => o.Orbiter);
foreach (string orbiterCode in orbiters)
{
Orbitable orbitable = new Orbitable(orbiterCode, currentOrbitable);
if (orbiterCode == "YOU")
{
me = orbitable;
}
if (orbiterCode == "SAN")
{
santa = orbitable;
}
currentOrbitable.Orbiters.Add(orbitable);
orbitablesToProcess.Enqueue(orbitable);
}
}
//Display(tree.CenterOfMass);
int distanceBetween = GetDistanceBetween(tree, me, santa);
Console.WriteLine($"Distance: {distanceBetween}");
}
public Orbitable(string code, Orbitable orbitee)
{
Code = code;
Orbitee = orbitee;
}
private static void Display(Orbitable centerOfMass, int depth = 0)
{
Console.WriteLine(new String('-', depth) + centerOfMass.Code);
centerOfMass.Orbiters.ForEach(o => Display(o, depth + 1));
}
private static int Weight(Orbitable centerOfMass, int depth = 0)
{
return(centerOfMass.Orbiters.Aggregate(depth, (acc, o) => acc + Weight(o, depth + 1)));
}