42 lines
1.1 KiB
Python
42 lines
1.1 KiB
Python
adj = {}
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with open("input.txt") as f:
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for line in f.read().split('\n'):
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[node1, node2] = line.split('-')
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if node1 not in adj:
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adj[node1] = set()
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if node2 not in adj:
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adj[node2] = set()
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if node1 in adj and node2 in adj:
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adj[node1].add(node2)
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adj[node2].add(node1)
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search = [['start']]
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paths = []
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while search:
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path = search.pop()
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current = path[-1]
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for cave in adj[current]:
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if cave == 'end':
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paths.append(path+[cave])
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elif cave.isupper() or cave not in path:
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search.append(path+[cave])
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print(len(paths))
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search = [(['start'], True)]
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paths = []
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while search:
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path, flag = search.pop()
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current = path[-1]
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for cave in adj[current]:
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if cave == 'end':
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paths.append(path+[cave])
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elif cave == 'start':
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continue # skip this case bc we can't go back
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elif cave.isupper() or cave not in path: # big cave or unvisited,
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search.append((path+[cave],flag)) # so explore further
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elif flag: # we still haven't visited a cave twice,
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search.append((path+[cave],False)) # so go there and explore, but remember we've used our exception
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print(len(paths)) |