30 lines
899 B
Python
30 lines
899 B
Python
with open('day20-input', 'r') as file:
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data = [l.strip('\n') for l in file]
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input = data[0][1:-1]
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from math import inf
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directions = {'N': 0-1j, 'E': 1+0j, 'S': 0+1j, 'W': -1+0j}
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stack = []
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distances = {0+0j: 0}
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pos = 0+0j
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next_distance = 1
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for c in input:
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if c in directions:
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pos += directions[c]
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distances[pos] = min(distances.get(pos, inf), next_distance)
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# This doesn't account for potentially shorter distances to other rooms along the old path to this room.
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# Works for both parts on this input though so no gain in fixing v(ツ)v
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# Backtracking those nodes would require keeping track of doors vs walls etc.
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elif c == '(':
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stack += [pos]
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elif c == '|':
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pos = stack[-1]
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elif c == ')':
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pos = stack.pop()
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next_distance = distances[pos] + 1
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print(max(distances.values())) # Part 1
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print(len([x for x in distances.values() if x >= 1000])) # Part 2
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