day20 - but including an assumption; might not work with other inputs

day20.py

@@ -0,0 +1,85 @@
+from tools.aoc import AOCDay
+from tools.coordinate import Coordinate, DistanceAlgorithm
+from typing import Any
+
+
+ZERO = Coordinate(0, 0, 0)
+
+
+class Particle:
+    def __init__(self, pos: Coordinate, vel: Coordinate, acc: Coordinate):
+        self.pos = pos
+        self.vel = vel
+        self.acc = acc
+
+    def move(self):
+        self.vel += self.acc
+        self.pos += self.vel
+
+    def dist(self):
+        return self.pos.getDistanceTo(ZERO, algorithm=DistanceAlgorithm.MANHATTAN, includeDiagonals=False)
+
+
+class Day(AOCDay):
+    inputs = [
+        [
+            (0, "input20_test"),
+            (457, "input20")
+        ],
+        [
+            (1, "input20_test2"),
+            (448, "input20")
+        ]
+    ]
+
+    def getParticles(self) -> list:
+        particles = []
+        for line in self.getInput():
+            p, v, a = line.split(", ")
+            p = Coordinate(*map(int, p[3:-1].split(",")))
+            v = Coordinate(*map(int, v[3:-1].split(",")))
+            a = Coordinate(*map(int, a[3:-1].split(",")))
+
+            particles.append(Particle(p, v, a))
+
+        return particles
+
+    def part1(self) -> Any:
+        particles = self.getParticles()
+        closest = 0
+        last_closest = list(range(-1, -1000, -1))
+        while len(set(last_closest)) != 1:
+            last_closest.append(closest)
+            last_closest.pop(0)
+            min_dist = 10e9
+            for i, p in enumerate(particles):
+                p.move()
+                if p.dist() < min_dist:
+                    closest = i
+                    min_dist = p.dist()
+
+        return closest
+
+    def part2(self) -> Any:
+        particles = self.getParticles()
+        for _ in range(1000):
+            pos_cache = {}
+            new_particles = []
+            for i, p in enumerate(particles.copy()):
+                p.move()
+                if p.pos not in pos_cache:
+                    new_particles.append(p)
+                    pos_cache[p.pos] = len(new_particles) - 1
+                else:
+                    if pos_cache[p.pos] >= 0:
+                        new_particles.pop(pos_cache[p.pos])
+                    pos_cache[p.pos] = -1
+
+            particles = new_particles
+
+        return len(particles)
+
+
+if __name__ == '__main__':
+    day = Day(2017, 20)
+    day.run(verbose=True)

inputs/input20_test

@@ -0,0 +1,2 @@
+p=< 3,0,0>, v=< 2,0,0>, a=<-1,0,0>
+p=< 4,0,0>, v=< 0,0,0>, a=<-2,0,0>

inputs/input20_test2

@@ -0,0 +1,4 @@
+p=<-6,0,0>, v=< 3,0,0>, a=< 0,0,0>
+p=<-4,0,0>, v=< 2,0,0>, a=< 0,0,0>
+p=<-2,0,0>, v=< 1,0,0>, a=< 0,0,0>
+p=< 3,0,0>, v=<-1,0,0>, a=< 0,0,0>