1 files changed, 126 insertions, 0 deletions
diff --git a/19/py/d12.py b/19/py/d12.py
new file mode 100644
index 0000000..878acc6
--- /dev/null
+++ b/19/py/d12.py
@@ -0,0 +1,126 @@
+import itertools
+#import primefac
+
+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 pt1(input):
+    return
+    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):
+    return
+    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)])
+
+    factors = [primefac.factorint(n) for n in (xs, ys, zs)]
+    nums = {}
+    for factor in factors:
+        for n in factor:
+            nums[n] = max(nums.get(n, 0), factor[n])
+    ans = 1
+    for n in nums:
+        ans *= n ** nums[n]
+    return ans
+
+if __name__ == "__main__":
+    input = open("../input/12", "r").readlines()
+    print(pt1(input))
+    print(pt2(input))