public override string Part2(string input)
{
var planets = RegexDeserializable.Deserialize <Point3>(input).ToArray();
var x = Cycle(new[] { planets[0].x, planets[1].x, planets[2].x, planets[3].x });
var y = Cycle(new[] { planets[0].y, planets[1].y, planets[2].y, planets[3].y });
var z = Cycle(new[] { planets[0].z, planets[1].z, planets[2].z, planets[3].z });
Console.WriteLine($"{x} {y} {z}");
return(Utils.lcm(Utils.lcm(x, y), z).ToString());
}
int simulate(string input, int iterations)
{
var planets = RegexDeserializable.Deserialize <Point3>(input).ToArray();
var velocities = new Point3[planets.Length];
foreach (var i in Enumerable.Range(0, iterations))
{
for (int i1 = 0; i1 < planets.Length; i1++)
{
for (int i2 = i1 + 1; i2 < planets.Length; i2++)
{
var p1 = planets[i1];
var p2 = planets[i2];
var adjustment = new Point3(Gravity(p1.x, p2.x), Gravity(p1.y, p2.y), Gravity(p1.z, p2.z));
velocities[i1] = velocities[i1].Offset(adjustment);
velocities[i2] = velocities[i2].Offset(adjustment.Scale(-1));
}
}
for (int i1 = 0; i1 < planets.Length; i1++)
{
planets[i1] = planets[i1].Offset(velocities[i1]);
}
/*
* Console.WriteLine(i + ":");
* for (int i1 = 0; i1 < planets.Length; i1++)
* {
* Console.WriteLine(planets[i1] + " " + velocities[i1]);
* }
*/
}
return(planets.Zip(velocities.AsEnumerable(), (p, v) => p.Magnitude * v.Magnitude).Sum());
}