76 lines
2.0 KiB
Python
76 lines
2.0 KiB
Python
#!/usr/bin/env python3
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from pathlib import Path
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def process_node(node, available_edges, visited):
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paths = []
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if node == "end":
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paths.append([node])
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return paths
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if node.islower():
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visited.add(node)
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neighbors = [n for e in available_edges if node in e for n in e if n != node]
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for n in neighbors:
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if n not in visited:
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nxt = process_node(n, available_edges, visited)
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paths += [[node] + p for p in nxt]
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if node in visited:
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visited.remove(node)
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return paths
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def process_node_twice(node, available_edges, visited, visited_twice):
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paths = deque()
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if node == "end":
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paths.append([node])
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return paths
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if node.islower():
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if node in visited and visited_twice:
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return paths
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elif node in visited and node != "start":
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visited_twice = node
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else:
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visited.add(node)
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neighbors = [n for e in available_edges if node in e for n in e if n != node]
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for n in neighbors:
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if n not in visited or visited_twice != node and n != "start":
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nxt = process_node_twice(n, available_edges, visited, visited_twice)
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paths += [[node] + p for p in nxt]
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if visited_twice == node:
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visited_twice = None
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elif node in visited:
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visited.remove(node)
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return paths
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def part_1(input):
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result = 0
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edges = []
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for line in input:
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n_start, n_end = line.strip().split('-')
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e = (n_start, n_end)
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edges.append(e)
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paths = process_node("start", edges, set())
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result = len(paths)
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print("Part 1 result:", result)
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def part_2(input):
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result = 0
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edges = []
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for line in input:
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n_start, n_end = line.strip().split('-')
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e = (n_start, n_end)
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edges.append(e)
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paths = process_node_twice("start", edges, set(), None)
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result = len(paths)
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print("Part 2 result:", result)
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input = list()
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p = Path(__file__).with_name('input.txt')
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with open(p) as f:
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input = f.readlines()
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part_1(input)
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part_2(input)
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