106 lines
2.8 KiB
Python
106 lines
2.8 KiB
Python
from collections import defaultdict
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import time
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import numpy as np
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DIM = 40
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EX = [
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".#....#####...#..",
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"##...##.#####..##",
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"##...#...#.#####.",
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"..#.....#...###..",
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"..#.#.....#....##",
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]
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def main():
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with open("day10.txt", "rt") as input_file:
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amap = [line.rstrip() for line in input_file.readlines()]
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# amap = [line.rstrip() for line in EX]
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asteroids = []
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for y, line in enumerate(amap):
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for x, value in enumerate(line):
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if value == "#":
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asteroids.append((x, y))
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# Part 1
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best_vis = 0
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best_pos = None
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for pos in asteroids:
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vis = num_visible_asts(asteroids, pos)
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if vis > best_vis:
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best_vis, best_pos = vis, pos
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print(f"Best visibility is {best_vis} at {best_pos}.")
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# Part 2
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pos = best_pos
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asteroids.remove(pos)
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destroyed = 0
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angles = defaultdict(list)
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for a in asteroids:
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angle = np.angle(np.complex(a[0] - pos[0], a[1] - pos[1]), deg=True)
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angles[angle].append(a)
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current_angle = -90.0
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while asteroids:
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print(f"Laser at {pos}.")
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print(f"Current angle: {current_angle}.")
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targets = angles[current_angle]
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try:
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next_angle = min([a for a in angles.keys() if a > current_angle])
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except ValueError:
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next_angle = -180.0
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if not targets:
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current_angle = next_angle
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continue
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print(f"Acquired targets {targets}.")
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nearest_target = min(targets, key=lambda t: dist_idea(pos, t))
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print(f"Nearest target: {nearest_target}.")
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# Pew!
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asteroids.remove(nearest_target)
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targets.remove(nearest_target)
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destroyed += 1
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print(f"Destroyed {nearest_target} -- total of {destroyed} asteroids.")
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if destroyed == 200:
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print(f"Destroyed 200th asteroid at {nearest_target}.")
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break
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current_angle = next_angle
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draw(asteroids, pos, [nearest_target])
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time.sleep(0.2)
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print(f"Answer: {100 * nearest_target[0] + nearest_target[1]}.")
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def draw(asteroids, station_pos, specials=[]):
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for y in range(DIM):
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print(str(y).zfill(2), end=" ")
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for x in range(DIM):
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if (x, y) == station_pos:
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print("@", end="")
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elif (x, y) in specials:
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print("X", end="")
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elif (x, y) in asteroids:
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print("█", end="")
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else:
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print(" ", end="")
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print()
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print(" " + "0123456789"*4)
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def num_visible_asts(asteroids, ref):
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asteroids = asteroids.copy()
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asteroids.remove(ref)
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angles = [np.angle(np.complex(a[0] - ref[0], a[1] - ref[1])) for a in asteroids]
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return len(set(angles))
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def dist_idea(a, b):
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return (a[0] - b[0]) ** 2 + (a[1] - b[1]) ** 2
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if __name__ == "__main__":
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main()
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