commit f40d5285f14dadd0f979c0ca56ecde71d9257541 · kot.pink/aoc

+12 -19
3.py
···

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       import sys

     

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       -
       import heapq

     

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       output_two = 0

     

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       output_twelve = 0

     

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       file = '3.input' if len(sys.argv) <= 1 else sys.argv[1]

     

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       for line in open(file).readlines():

     

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           first_seen = {} # digit to first index

     

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           last_seen = {} # digit to last index

     

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           for i, digit in enumerate(line.strip()):

     

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               first_seen.setdefault(int(digit), i)

     

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               last_seen[int(digit)] = i

     

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           max_all = max(first_seen.keys()) # largest digit (always included)

     

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           if last_seen[max_all] > first_seen[max_all]: # if it appears twice, just use it

     

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               output_two += max_all * 11

     

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               continue

     

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           line = line.strip()

     

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           for n in [2, 12]:

     

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               result = [-1] * n

     

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               for it in range(n):

     

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                   right = list(enumerate(line[:-(n-1)+it or len(line)]))

     

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                   allowed = [(i, d) for i, d in right if i > max(result)]

     

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                   pick = max(allowed, key=lambda a: a[1])

     

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                   result[it] = pick[0]

     

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           try:

     

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               # first search right of the max digit

     

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               max_right = max(digit for digit, i in last_seen.items() if i > first_seen[max_all])

     

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               output_two += max_all * 10 + max_right

     

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           except ValueError:

     

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               # search left for max digit

     

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               max_left = max(digit for digit, i in last_seen.items() if i < first_seen[max_all])

     

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               output_two += max_left * 10 + max_all

     

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               if n == 2:

     

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                   output_two += int("".join(line[i] for i in result))

     

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               elif n == 12:

     

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                   output_twelve += int("".join(line[i] for i in result))

     

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       print(f'p1: {output_two}')

     

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       print(f'p2: {output_twelve}')