advent_of_code_2021

commit bbe48acdc50b4999423ed00bd15b2c0d23d9e1cf
parent 40ae9ac2d3f794b51685a439516e4b220b8b703e
Author: Eamon Caddigan <eamon.caddigan@gmail.com>
Date:   Sun, 19 Dec 2021 20:38:05 -0500

Solution to day 19, part 2

Diffstat:
A
day19_part2.py
 | 
37
+++++++++++++++++++++++++++++++++++++

1 file changed, 37 insertions(+), 0 deletions(-)
diff --git a/day19_part2.py b/day19_part2.py
@@ -0,0 +1,37 @@
+#!/usr/bin/env python
+"""Advent of Code 2021, day 19 (part 2): Beacon Scanner
+Given positions (but not consistent frame of reference), find the overlap
+between a set of beacons detected by several scanners"""
+
+#  One of those plesant situations where my solution to part 1 solves part 2
+
+from typing import List
+import numpy as np
+from scipy.spatial.distance import cdist
+from day19_part1 import (EXAMPLE_INPUT,
+                         parse_input,
+                         create_beacon_network)
+from utils import get_puzzle_input
+
+def find_beacon_distance(transformation_list: List[np.ndarray]) -> np.ndarray:
+    """Return a distance matrix of the beacons by pulling out the translation
+    component of the transformation matrices"""
+    scanner_locations = np.array(
+        [x[3, 0:3] for x in transformation_list]
+    )
+    return cdist(scanner_locations, scanner_locations, metric='cityblock')
+
+def solve_puzzle(input_string: str) -> int:
+    """Return the numeric solution to the puzzle"""
+    return find_beacon_distance(
+        create_beacon_network(parse_input(input_string))[1]
+    ).max()
+
+def main() -> None:
+    """Run when the file is called as a script"""
+    assert solve_puzzle(EXAMPLE_INPUT) == 3621
+    print("Maximum distance between scanners:",
+          solve_puzzle(get_puzzle_input(19)))
+
+if __name__ == "__main__":
+    main()