2017 day 20 part 2

2017/20/particle.py

@@ -3,11 +3,6 @@
 def man_dist(tup):
     return sum(map(abs, tup))
 
-import sys
-import re
-pattern = re.compile(r"<([0-9-]*),([0-9-]*),([0-9-]*)>")
-data = [[(int(c[0]), int(c[1]), int(c[2])) for c in p] for p in [pattern.findall(l.strip()) for l in sys.stdin.readlines()]]
-
 def update_particle(p):
     return (
         tuple(map(sum, zip(p[0], p[1]))),
@@ -15,12 +10,36 @@ def update_particle(p):
         p[2],
     )
 
-while True:
-    data = list(map(update_particle, data))
-
-    min_dist, min_p = None, None
-    for i, particle in enumerate(data):
-        md = man_dist(particle[0])
-        if min_p is None or md < min_dist:
-            min_p, min_dist = i, md
+def part1(particles):
+    stability = 0
+    previous, min_p = None, None
+    while stability < 300:
+        previous = min_p
+        stability += 1
+        min_dist = None
+        particles = list(map(update_particle, particles))
+        for i, particle in enumerate(particles):
+            md = man_dist(particle[0])
+            if min_p is None or min_dist is None or md < min_dist:
+                min_p, min_dist = i, md
+        if previous != min_p:
+            stability = 0
     print(min_p)
+
+def part2(particles):
+    number = len(particles)
+    while True:
+        particles = list(map(update_particle, particles))
+        positions = next(zip(*particles))
+        if len(positions) != len(set(positions)):
+            particles = list(filter(lambda p: positions.count(p[0]) == 1, particles))
+            number = len(particles)
+            print(number)
+
+if __name__ == '__main__':
+    import sys
+    import re
+    pattern = re.compile(r"<([0-9-]*),([0-9-]*),([0-9-]*)>")
+    data = [[(int(c[0]), int(c[1]), int(c[2])) for c in p] for p in [pattern.findall(l.strip()) for l in sys.stdin.readlines()]]
+    run = part2 if any(arg in map(str.strip, map(str.lower, sys.argv)) for arg in ('-c', '--collisions')) else part1
+    run(data)