From 0d473b23584e9f8e87856db167d285cd899347a4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Gustav=20S=C3=B6rn=C3=A4s?= <gusso230@student.liu.se>
Date: Wed, 18 Dec 2019 20:37:36 +0100
Subject: Implement LCM and remove coverage

Runtime is at 6 seconds with pypy oof.
---
 19/py/d12.py | 17 +++++------------
 1 file changed, 5 insertions(+), 12 deletions(-)

(limited to '19/py/d12.py')

diff --git a/19/py/d12.py b/19/py/d12.py
index 878acc6..90ae437 100644
--- a/19/py/d12.py
+++ b/19/py/d12.py
@@ -1,5 +1,5 @@
 import itertools
-#import primefac
+import math
 
 class Moon(object):
     def __init__(self, x, y, z):
@@ -47,8 +47,10 @@ class Moon(object):
     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):
-    return
     moons = []
 
     for line in input:
@@ -93,7 +95,6 @@ def get_cycle(init_pos, init_vel):
             return iters
 
 def pt2(input):
-    return
     moons = []
     xs = 0
     ys = 0
@@ -110,15 +111,7 @@ def pt2(input):
     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
+    return lcm(lcm(xs, ys), zs)
 
 if __name__ == "__main__":
     input = open("../input/12", "r").readlines()
-- 
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