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import itertools
import math
class Moon(object):
def __init__(self, x, y, z):
self.x = x
self.y = y
self.z = z
self.dx = 0
self.dy = 0
self.dz = 0
def step(self):
self.x += self.dx
self.y += self.dy
self.z += self.dz
def gx(self, other):
if self.x < other.x:
self.dx += 1
other.dx -= 1
def gy(self, other):
if self.y < other.y:
self.dy += 1
other.dy -= 1
def gz(self, other):
if self.z < other.z:
self.dz += 1
other.dz -= 1
def gravity(self, other):
self.gx(other)
self.gy(other)
self.gz(other)
def get_x(self):
return self.x, self.dx
def get_y(self):
return self.y, self.dy
def get_z(self):
return self.z, self.dz
def get(self):
return self.get_x, self.get_y, self.get_z
def lcm(a, b):
return a*b // math.gcd(a, b)
def pt1(input):
moons = []
for line in input:
dims = line.rstrip().split(",")
x = int(dims[0][3:])
y = int(dims[1][3:])
z = int(dims[2][3:-1])
moons.append(Moon(x, y, z))
for _ in range(1000):
for pair in itertools.permutations(moons, 2):
pair[0].gravity(pair[1])
for moon in moons:
moon.step()
tot = 0
for moon in moons:
pot = abs(moon.x) + abs(moon.y) + abs(moon.z)
kin = abs(moon.dx) + abs(moon.dy) + abs(moon.dz)
tot += pot*kin
return tot
def get_cycle(init_pos, init_vel):
initial = tuple(init_pos)
pos = init_pos.copy()
vel = init_vel.copy()
iters = 0
while 1:
for i, j in itertools.permutations(range(4), 2):
if i == j:
continue
if pos[i] < pos[j]:
vel[i] += 1
vel[j] -= 1
for i in range(4):
pos[i] += vel[i]
iters += 1
if pos[0] == initial[0] and pos[1] == initial[1] and \
pos[2] == initial[2] and pos[3] == initial[3] and \
vel[0] == 0 and vel[1] == 0 and \
vel[2] == 0 and vel[3] == 0:
return iters
def pt2(input):
moons = []
xs = 0
ys = 0
zs = 0
for line in input:
dims = line.rstrip().split(",")
x = int(dims[0][3:])
y = int(dims[1][3:])
z = int(dims[2][3:-1])
moons.append(Moon(x, y, z))
xs = get_cycle([moon.x for moon in moons], [0 for _ in range(4)])
ys = get_cycle([moon.y for moon in moons], [0 for _ in range(4)])
zs = get_cycle([moon.z for moon in moons], [0 for _ in range(4)])
return lcm(lcm(xs, ys), zs)
if __name__ == "__main__":
input = open("../input/12", "r").readlines()
print(pt1(input))
print(pt2(input))
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