2017: d20: ex1: add solution

2017/d20/ex1/ex1.py

@@ -0,0 +1,52 @@
+#!/usr/bin/env python
+
+import sys
+from typing import NamedTuple
+
+
+class Point(NamedTuple):
+    x: int
+    y: int
+    z: int
+
+
+class Particle(NamedTuple):
+    pos: Point
+    vel: Point
+    acc: Point
+
+    @classmethod
+    def from_str(cls, input: str) -> "Particle":
+        p, v, a = input.split(", ")
+        return cls(
+            Point(*map(int, p[3:-1].split(","))),
+            Point(*map(int, v[3:-1].split(","))),
+            Point(*map(int, a[3:-1].split(","))),
+        )
+
+
+def solve(input: str) -> int:
+    def parse(input: str) -> list[Particle]:
+        return [Particle.from_str(line) for line in input.splitlines()]
+
+    def dist(point: Point, other: Point) -> int:
+        return sum(abs(a - b) for a, b in zip(point, other))
+
+    particles = parse(input)
+    orig = Point(0, 0, 0)
+    # Lowest acceleration will be closest to origin as time tends to infinity
+    # Same logic for velocity and position
+    closest_particle = min(
+        particles,
+        key=lambda p: (dist(p.acc, orig), dist(p.vel, orig), dist(p.pos, orig)),
+    )
+    return particles.index(closest_particle)
+
+
+def main() -> None:
+    input = sys.stdin.read()
+    print(solve(input))
+
+
+if __name__ == "__main__":
+    main()