Jake Pullen
51 lines
1.9 KiB
Python
51 lines
1.9 KiB
Python
with open(r'advent_of_code\2023\24\input.txt', 'r') as file:
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input_data = file.read()
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test_input = '''19, 13, 30 @ -2, 1, -2
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18, 19, 22 @ -1, -1, -2
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20, 25, 34 @ -2, -2, -4
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12, 31, 28 @ -1, -2, -1
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20, 19, 15 @ 1, -5, -3'''
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#input_data = test_input
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input_lines = input_data.split('\n')
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class Hailstone:
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def __init__(self, start_x, start_y, start_z, velocity_x, velocity_y, velocity_z):
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self.start_x = start_x
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self.start_y = start_y
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self.start_z = start_z
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self.velocity_x = velocity_x
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self.velocity_y = velocity_y
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self.velocity_z = velocity_z
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self.a = velocity_y
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self.b = -velocity_x
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self.c = velocity_y * start_x - velocity_x * start_y
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def __repr__(self):
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return "Hailstone{" + f"a={self.a}, b={self.b}, c={self.c}" + "}"
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# Parse input lines into Hailstone objects
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hailstones = [Hailstone(*map(int, line.replace("@", ",").split(","))) for line in input_lines]
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total_intersections = 0
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# Check each pair of hailstones for intersection
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for i, hailstone1 in enumerate(hailstones):
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for hailstone2 in hailstones[:i]:
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a1, b1, c1 = hailstone1.a, hailstone1.b, hailstone1.c
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a2, b2, c2 = hailstone2.a, hailstone2.b, hailstone2.c
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# If lines are parallel, they do not intersect
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if a1 * b2 == b1 * a2:
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continue
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# Calculate intersection point
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x = (c1 * b2 - c2 * b1) / (a1 * b2 - a2 * b1)
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y = (c2 * a1 - c1 * a2) / (a1 * b2 - a2 * b1)
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# Check if intersection point is within bounds
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if 200000000000000 <= x <= 400000000000000 and 200000000000000 <= y <= 400000000000000:
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# Check if intersection point is in the same direction as the hailstones' velocities
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if all((x - hs.start_x) * hs.velocity_x >= 0 and (y - hs.start_y) * hs.velocity_y >= 0 for hs in (hailstone1, hailstone2)):
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total_intersections += 1
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print(total_intersections) |