commit 119b6797720051c4aaaf8f6f52ac68ca2f51b7a2
parent f6fcb47859f0698382b0ceadb3d3e69a4a0eb8ee
Author: Eamon Caddigan <eamon.caddigan@gmail.com>
Date: Sat, 11 Dec 2021 05:42:57 -0500
Solution to day 11, part 2
Diffstat:
| A | day11_part2.py | | | 50 | ++++++++++++++++++++++++++++++++++++++++++++++++++ |
1 file changed, 50 insertions(+), 0 deletions(-)
diff --git a/day11_part2.py b/day11_part2.py
@@ -0,0 +1,50 @@
+#!/usr/bin/env python
+"""Advent of Code 2021, day 11 (part 2): Flashing octopuses
+For part 2, we're simulating bioluminescent octopuses again, and this time we
+want to find the `step` at which they all flash simultaneously."""
+
+# I think I can pretty much use everything from part 1 here and just update the
+# solving code
+
+import numpy as np
+from day11_part1 import (EXAMPLE_INPUT,
+ convert_input_to_array,
+ simulate_step)
+from utils import get_puzzle_input
+
+def all_flashed(energy_levels: np.ndarray) -> bool:
+ """Detects the moment when all energy levels have been reset to 0"""
+ return not energy_levels.any()
+
+def run_simulation_until_synchronized(energy_levels: np.ndarray) -> int:
+ """Run the simulation from the initial 2d array of energy levels until all
+ octopuses flash at the same time, and return the step number at which it
+ occurred"""
+ # Leaning on Python's nice iterator behavior and for/else syntax: no need
+ # to risk an infinite loop, we can set a "reasonable" limit of iterations
+ # up front. Also I just love underscores in numeric literals.
+ for num_steps in range(1_000_000):
+ energy_levels = simulate_step(energy_levels)[0]
+ if all_flashed(energy_levels):
+ break
+ else:
+ raise RuntimeError("No synchronized flash detected after many steps")
+
+ # We're counting steps from 1 apparently
+ return num_steps + 1
+
+def solve_puzzle(input_string: str) -> int:
+ """Return the numeric solution to the puzzle"""
+ return run_simulation_until_synchronized(
+ convert_input_to_array(input_string)
+ )
+
+def main() -> None:
+ """Run when the file is called as a script"""
+ assert solve_puzzle(EXAMPLE_INPUT) == 195
+ # Is that you, Shevek?
+ print("Number of steps to simultaneity:",
+ solve_puzzle(get_puzzle_input(11)))
+
+if __name__ == "__main__":
+ main()
