public Moon(Moon m)
{
x = m.x;
y = m.y;
z = m.z;
dx = dy = dz = 0;
}
public void ApplyGravity(Moon m)
{
if (x < m.x)
{
dx += 1;
m.dx -= 1;
}
else if (x > m.x)
{
dx -= 1;
m.dx += 1;
}
if (y < m.y)
{
dy += 1;
m.dy -= 1;
}
else if (y > m.y)
{
dy -= 1;
m.dy += 1;
}
if (z < m.z)
{
dz += 1;
m.dz -= 1;
}
else if (z > m.z)
{
dz -= 1;
m.dz += 1;
}
}
private void ApplyGravity(Moon moon1, Moon moon2)
{
var xDiff = moon1.Position.X - moon2.Position.X;
if (xDiff != 0)
{
xDiff /= Math.Abs(xDiff);
}
var yDiff = moon1.Position.Y - moon2.Position.Y;
if (yDiff != 0)
{
yDiff /= Math.Abs(yDiff);
}
var zDiff = moon1.Position.Z - moon2.Position.Z;
if (zDiff != 0)
{
zDiff /= Math.Abs(zDiff);
}
moon1.Velocity.X -= xDiff;
moon2.Velocity.X += xDiff;
moon1.Velocity.Y -= yDiff;
moon2.Velocity.Y += yDiff;
moon1.Velocity.Z -= zDiff;
moon2.Velocity.Z += zDiff;
}
public void AdjustVelocityFromGravityOf(Moon m)
{
if (m.X > this.X)
{
XVelocity++;
}
else if (m.X < this.X)
{
XVelocity--;
}
if (m.Y > this.Y)
{
YVelocity++;
}
else if (m.Y < this.Y)
{
YVelocity--;
}
if (m.Z > this.Z)
{
ZVelocity++;
}
else if (m.Z < this.Z)
{
ZVelocity--;
}
}
public static void AdjustVelocities(Moon moon1, Moon moon2)
{
moon1.Velocity.X += moon1.Position.X < moon2.Position.X ? 1 : moon1.Position.X == moon2.Position.X ? 0 : -1;
moon2.Velocity.X += moon1.Position.X > moon2.Position.X ? 1 : moon1.Position.X == moon2.Position.X ? 0 : -1;
moon1.Velocity.Y += moon1.Position.Y < moon2.Position.Y ? 1 : moon1.Position.Y == moon2.Position.Y ? 0 : -1;
moon2.Velocity.Y += moon1.Position.Y > moon2.Position.Y ? 1 : moon1.Position.Y == moon2.Position.Y ? 0 : -1;
moon1.Velocity.Z += moon1.Position.Z < moon2.Position.Z ? 1 : moon1.Position.Z == moon2.Position.Z ? 0 : -1;
moon2.Velocity.Z += moon1.Position.Z > moon2.Position.Z ? 1 : moon1.Position.Z == moon2.Position.Z ? 0 : -1;
}
private void ApplyGravity()
{
var pairs = Moons.SelectMany((first, i) => Moons.Skip(i + 1).Select(second => (first, second)));
foreach (var pair in pairs)
{
Moon.AdjustVelocities(pair.first, pair.second);
}
}
public Moon(Moon m)
{
this.X = m.X;
this.Y = m.Y;
this.Z = m.Z;
this.XVelocity = m.XVelocity;
this.YVelocity = m.YVelocity;
this.ZVelocity = m.ZVelocity;
}
void SimulateZCoordenates(Moon m, Moon otherMoon)
{
if (m.z > otherMoon.z)
{
m.vz--;
otherMoon.vz++;
}
else if (m.z < otherMoon.z)
{
m.vz++;
otherMoon.vz--;
}
}
void SimulateYCoordenates(Moon m, Moon otherMoon)
{
if (m.y > otherMoon.y)
{
m.vy--;
otherMoon.vy++;
}
else if (m.y < otherMoon.y)
{
m.vy++;
otherMoon.vy--;
}
}
void SimulateXCoordenates(Moon m, Moon otherMoon)
{
if (m.x > otherMoon.x)
{
m.vx--;
otherMoon.vx++;
}
else if (m.x < otherMoon.x)
{
m.vx++;
otherMoon.vx--;
}
}
// To apply gravity, consider every pair of moons.On each axis(x, y, and z), the velocity of each moon changes
// by exactly +1 or -1 to pull the moons together.For example, if Ganymede has an x position of 3, and Callisto
// has a x position of 5, then Ganymede's x velocity changes by +1 (because 5 > 3) and Callisto's x velocity
// changes by -1 (because 3 < 5). However, if the positions on a given axis are the same, the velocity on that
// axis does not change for that pair of moons.
public static void ApplyGravity(List <Moon> moons)
{
for (int i = 0; i < (moons.Count - 1); i++)
{
for (int j = i + 1; j < moons.Count; j++)
{
Moon currentMoon = moons[i];
Moon otherMoon = moons[j];
int positionXDiff = currentMoon.positionX - otherMoon.positionX;
if (positionXDiff > 0)
{
currentMoon.velocityX--;
otherMoon.velocityX++;
}
else if (positionXDiff < 0)
{
currentMoon.velocityX++;
otherMoon.velocityX--;
}
int positionYDiff = currentMoon.positionY - otherMoon.positionY;
if (positionYDiff > 0)
{
currentMoon.velocityY--;
otherMoon.velocityY++;
}
else if (positionYDiff < 0)
{
currentMoon.velocityY++;
otherMoon.velocityY--;
}
int positionZDiff = currentMoon.positionZ - otherMoon.positionZ;
if (positionZDiff > 0)
{
currentMoon.velocityZ--;
otherMoon.velocityZ++;
}
else if (positionZDiff < 0)
{
currentMoon.velocityZ++;
otherMoon.velocityZ--;
}
}
}
}
private static List <Moon> GetMoons(string input)
{
List <Moon> moons = new List <Moon>();
string[] lines = input.Split(Environment.NewLine);
//<x=-5, y=-4, z=-4>
Regex regex = new Regex(@"<x=(?<x>-?\d+), y=(?<y>-?\d+), z=(?<z>-?\d+)");
foreach (string line in lines)
{
Match m = regex.Match(line);
if (m.Success)
{
Moon moon = new Moon(int.Parse(m.Groups["x"].Value),
int.Parse(m.Groups["y"].Value),
int.Parse(m.Groups["z"].Value));
moons.Add(moon);
}
}
return(moons);
}
public void Part2()
{
Moon[] Data = TestData;
Moon[] InitData = new Moon[Data.Length];
for (int m = 0; m < Data.Length; m++)
{
InitData[m] = new Moon(Data[m]);
}
int step = 1;
Step(Data);
while (!SamePos(InitData, Data))
{
Step(Data);
step++;
}
Console.WriteLine("Day12 Part2 Result = {0}", step);
}
public bool SamePos(Moon m)
{
return((m.x == x) && (m.y == y) && (m.z == z) && (m.dx == dx) && (m.dy == y) && (m.dz == z));
}
public static void Problem(int iterations, string[] moonStrings, out int energyAfterIterations, out long returnToOrigin)
{
if (moonStrings == null)
{
throw new NullReferenceException();
}
Moon[] moons = new Moon[moonStrings.Length];
Moon[] originalMoons = new Moon[moonStrings.Length];
for (int i = 0; i < moonStrings.Length; i++)
{
moons[i] = new Moon(moonStrings[i]);
originalMoons[i] = new Moon(moonStrings[i]);
}
/*
* The x, y, and z values are independent - for part 2, find the repeat periods of
* each individual part and then find the least common multiple of the 3 values
*/
long xPeriod = Int64.MaxValue;
long yPeriod = Int64.MaxValue;
long zPeriod = Int64.MaxValue;
//fixed number of iterations for part 1
for (int i = 1; i <= iterations; i++)
{
ApplyGravityAndMove(moons);
//check if x's, y's, or z's are in initial state - if so, set period for that axis
if (xPeriod == Int64.MaxValue && CompareX(originalMoons, moons))
{
xPeriod = i;
}
if (yPeriod == Int64.MaxValue && CompareY(originalMoons, moons))
{
yPeriod = i;
}
if (zPeriod == Int64.MaxValue && CompareZ(originalMoons, moons))
{
zPeriod = i;
}
////debugging use only
//Console.WriteLine($"after {(i + 1).ToString()} steps:");
//for (int j = 0; j < 4; j++)
//{
// Console.WriteLine(moons[j].ToString());
//}
}
int energy = 0;
for (int i = 0; i < 4; i++)
{
energy += moons[i].Energy;
}
energyAfterIterations = energy;
//loop until repeat periods for X, Y, and Z found for part 2
long loops = iterations;
while (xPeriod == Int64.MaxValue || yPeriod == Int64.MaxValue || zPeriod == Int64.MaxValue)
{
ApplyGravityAndMove(moons);
loops++;
//check if x's, y's, or z's are in initial state - if so, set period for that axis
if (xPeriod == Int64.MaxValue && CompareX(originalMoons, moons))
{
xPeriod = loops;
}
if (yPeriod == Int64.MaxValue && CompareY(originalMoons, moons))
{
yPeriod = loops;
}
if (zPeriod == Int64.MaxValue && CompareZ(originalMoons, moons))
{
zPeriod = loops;
}
}
returnToOrigin = LCM(xPeriod, LCM(yPeriod, zPeriod));
//debugging:
//Console.WriteLine($"xPeriod:{xPeriod.ToString()},yPeriod:{yPeriod.ToString()},zPeriod:{zPeriod.ToString()}");
}
public void ApplyGravity(Moon m)
{
VX += m.X.CompareTo(X);
VY += m.Y.CompareTo(Y);
VZ += m.Z.CompareTo(Z);
}