47 lines
1.2 KiB
Python
47 lines
1.2 KiB
Python
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input = 312051
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import numpy as np
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num_rings = 1000
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rings_sizes = np.empty(num_rings, dtype=np.int64)
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rings_sizes[0] = 1
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for i in range(1, num_rings):
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rings_sizes[i] = 8*i
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rings_ends = rings_sizes.cumsum()
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def find_position(number):
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ring_idx = (rings_ends >= number).argmax()
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pos_on_ring = number - rings_ends[ring_idx-1] if ring_idx > 0 else 1
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return ring_idx, pos_on_ring
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def distance(number):
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ring_idx, pos_on_ring = find_position(number)
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ring_pos_dist = abs(pos_on_ring%(ring_idx*2)-ring_idx)
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return ring_idx + ring_pos_dist
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print(distance(input)) # Part 1
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mem_plane_rings = 20
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mp_offset = mem_plane_rings
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mp_size = mem_plane_rings*2+1
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mem_plane = np.zeros((mp_size, mp_size), dtype=np.int64)
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directions = np.array([[0,1], [-1,0], [0,-1], [1,0]], dtype=np.int32)
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direction = -1
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position = np.array((mp_offset, mp_offset), dtype=np.int32)
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mem_plane[mp_offset, mp_offset] = 1
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for i in range((mp_size-2)**2):
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if mem_plane[tuple(position + directions[(direction+1)%4])] == 0:
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direction = (direction+1) % 4
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position += directions[direction]
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x, y = position
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mem_plane[x,y] = mem_plane[x-1:x+2, y-1:y+2].sum()
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if mem_plane[x,y] > input:
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print(mem_plane[x,y]) # Part 2
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break
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