55 lines
1.1 KiB
Python
55 lines
1.1 KiB
Python
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""" day 5 part 1 """
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import fileinput
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import collections
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deps = collections.defaultdict(set) # map post -> [pre]
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reader = fileinput.input()
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for line in reader:
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line = line.strip()
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if not line:
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break
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pre,post = line.split('|')
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deps[post].add(pre)
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total = 0
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def print_page(seq, page, deps, printed, wanted):
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if page in printed:
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return
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for dep in deps[page]:
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if dep in wanted:
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print_page(seq, dep, deps, printed, wanted)
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seq.append(page)
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printed.add(page)
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for line in reader:
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seq = line.strip().split(',')
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wanted = set(seq)
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seen = set()
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safe = True
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for page in seq:
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# print(f'{seen} -> {page}')
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for dep in deps[page]:
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if dep in wanted and dep not in seen:
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# print(f' {page} missing {dep}')
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safe = False
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seen.add(page)
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if not safe:
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seq = []
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printed = set()
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for page in wanted:
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print_page(seq, page, deps, printed, wanted)
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val = int(seq[len(seq)//2])
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print(f'{seq} -> {val}')
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total += int(val)
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print(total)
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