From ae041ba1d58b9b567719e9813d63d4f815d93fdf Mon Sep 17 00:00:00 2001
From: Dece <shgck@pistache.land>
Date: Thu, 12 Dec 2019 22:42:39 +0100
Subject: [PATCH] Day 12 done better

---
 2019/day12.py | 76 ++++++++++++++-------------------------------------
 1 file changed, 20 insertions(+), 56 deletions(-)

diff --git a/2019/day12.py b/2019/day12.py
index 3767bb0..706bb69 100644
--- a/2019/day12.py
+++ b/2019/day12.py
@@ -2,74 +2,38 @@ import itertools
 import re
 
 
-class Moon:
-
-    def __init__(self, coords, velocity):
-        self.pos = coords
-        self.vel = velocity
-
-    def __str__(self):
-        return "{} {}".format(self.pos, self.vel)
-
-    def get_energy(self):
-        return self.get_pot_energy() * self.get_kin_energy()
-
-    def get_pot_energy(self):
-        return abs(self.pos.x) + abs(self.pos.y) + abs(self.pos.z)
-
-    def get_kin_energy(self):
-        return abs(self.vel.x) + abs(self.vel.y) + abs(self.vel.z)
-
-
-class Vector:
-
-    def __init__(self, x=0, y=0, z=0):
-        self.x = x
-        self.y = y
-        self.z = z
-
-    def __str__(self):
-        return "({}, {}, {})".format(self.x, self.y, self.z)
-
-    def __add__(self, other):
-        return Vector(self.x + other.x, self.y + other.y, self.z + other.z)
-
 
 def main():
     with open("day12.txt", "rt") as input_file:
         lines = input_file.readlines()
     vector_re = re.compile(r"<x=(-?\d+), y=(-?\d+), z=(-?\d+)>")
     matches = [vector_re.match(line.rstrip()) for line in lines]
-    coords = [Vector(*(int(v) for v in match.groups())) for match in matches]
-    moons = [Moon(coord, Vector()) for coord in coords]
+    coords = [list([int(i) for i in match.groups()]) for match in matches]
+    moons = [[coord, [0] * 3] for coord in coords]
+
+    # Part 1
     for _ in range(1000):
         do_step(moons)
-    print("Total moons energy:", sum(moon.get_energy() for moon in moons))
+    print("Total moons energy:", sum(get_energy(moon) for moon in moons))
 
 def do_step(moons):
-    apply_gravities(moons)
-    apply_velocities(moons)
+    for a, b in itertools.combinations(moons, 2):
+        for d in range(3):
+            if a[0][d] > b[0][d]:
+                a[1][d] -= 1
+                b[1][d] += 1
+            elif a[0][d] < b[0][d]:
+                a[1][d] += 1
+                b[1][d] -= 1
 
-def apply_gravities(moons):
-    for pairs in itertools.combinations(moons, 2):
-        apply_gravity(*pairs)
-
-def apply_gravity(a, b):
-    for c in ["x", "y", "z"]:
-        a_pos_c = getattr(a.pos, c)
-        b_pos_c = getattr(b.pos, c)
-        a_vel_c = getattr(a.vel, c)
-        b_vel_c = getattr(b.vel, c)
-        if a_pos_c > b_pos_c:
-            setattr(a.vel, c, a_vel_c - 1)
-            setattr(b.vel, c, b_vel_c + 1)
-        elif a_pos_c < b_pos_c:
-            setattr(a.vel, c, a_vel_c + 1)
-            setattr(b.vel, c, b_vel_c - 1)
-
-def apply_velocities(moons):
     for moon in moons:
-        moon.pos += moon.vel
+        for d in range(3):
+            moon[0][d] += moon[1][d]
+
+def get_energy(moon):
+    pot = sum(abs(moon[0][d]) for d in range(3))
+    ket = sum(abs(moon[1][d]) for d in range(3))
+    return pot * ket
 
 
 if __name__ == "__main__":