75 lines
1.7 KiB
Python
75 lines
1.7 KiB
Python
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import pprint
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import itertools
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import fileinput
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nodes = []
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edges = []
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for raw in fileinput.input():
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line = raw.strip()
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if line == '': continue
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[a,b] = line.split('-')
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nodes += [a, b]
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edges.append((a, b))
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nodes = list(set(nodes))
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nodes.sort()
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graph = [[0 for j in range(len(nodes))] for i in range(len(nodes))]
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#pprint.pprint(graph)
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for (a,b) in edges:
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i, j = nodes.index(a), nodes.index(b)
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graph[i][j] = 1
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graph[j][i] = 1
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visit_only_once = [e for e in nodes if e.lower() == e and e != 'start' and e != 'end']
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start_index = nodes.index('start')
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end_index = nodes.index('end')
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nodes_d = [(i,e) for i,e in enumerate(nodes)]
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print(f'{nodes_d=}')
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print(f'{visit_only_once=}')
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visit_only_once_index = [nodes.index(e) for e in visit_only_once]+[start_index, end_index]
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def explore_path(stack, level, locked, s, did_visit_twice):
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edges = [i for i,e in enumerate(graph[s]) if e]
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if s == end_index:
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return [s] + [stack]
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paths = []
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for edge in edges:
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if edge == start_index: continue
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if edge in visit_only_once_index:
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if edge in locked:
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if not did_visit_twice and edge != start_index and edge != end_index:
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did_visit_twice = True
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else:
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continue
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locked.add(edge)
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#print(f'{level=} , {nodes[edge]=}, {new_locked=}, {at_most=} ')
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paths += explore_path([s]+stack, level+1, locked.copy(), edge, did_visit_twice)
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return paths
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print('start exploring...')
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paths = explore_path([], 0, set(), start_index, False)
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all_paths = [ ''.join(map(str, p)) for p in paths ]
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res = list(set(all_paths))
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for p in res:
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new_p = list(map(int, list(p)))
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#print([ nodes[i] for i in list(reversed(new_p))])
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#print(res)
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print(f'There are {len(res)} paths')
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