2019: d12: ex1: add solution

2019/d12/ex1/ex1.py

@@ -0,0 +1,50 @@
+#!/usr/bin/env python
+
+
+import re
+import sys
+from dataclasses import dataclass
+
+
+@dataclass
+class Position:
+    x: int
+    y: int
+    z: int
+
+
+def line_to_pos(l: str) -> Position:
+    "<x=4, y=1, z=1>"
+    regex = r"<x=(?P<x>[^,]*), y=(?P<y>[^,]*), z=(?P<z>[^,]*)>"
+    match = re.search(regex, l)
+    assert match is not None  # Sanity check
+    return Position(*(int(match.group(g)) for g in ("x", "y", "z")))
+
+
+def main() -> None:
+    asteroids = [line_to_pos(line) for line in sys.stdin.readlines()]
+    velocities = [Position(0, 0, 0) for __ in asteroids]
+
+    for __ in range(1000):
+        for orig, v in zip(asteroids, velocities):
+            for other in asteroids:
+                if orig.x != other.x:
+                    v.x += 1 if orig.x < other.x else -1
+                if orig.y != other.y:
+                    v.y += 1 if orig.y < other.y else -1
+                if orig.z != other.z:
+                    v.z += 1 if orig.z < other.z else -1
+
+        for asteroid, v in zip(asteroids, velocities):
+            asteroid.x += v.x
+            asteroid.y += v.y
+            asteroid.z += v.z
+
+    pot = (abs(p.x) + abs(p.y) + abs(p.z) for p in asteroids)
+    kin = (abs(v.x) + abs(v.y) + abs(v.z) for v in velocities)
+
+    print(sum(p * k for p, k in zip(pot, kin)))
+
+
+if __name__ == "__main__":
+    main()