My Advent of Code solutions in Python.
kevinyap.ca/2019/12/going-fast-in-advent-of-code/
advent-of-code
python
Update 2017/day07.py
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+29
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2017/day07.py
+29
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2017/day07.py
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import sys
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import re
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import fileinput
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print 'Name of bottom program:', root.name
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BAD_WEIGHTS = {}
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def program_weight(node):
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if not node.aboves:
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return node.weight
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weights = [program_weight(a) for a in node.aboves]
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# Since we're performing DFS, we are guaranteed to encounter the problem
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# disc here first; therefore, we compute the correct answer and exit.
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# Keep track of discs whose children have different weights
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if len(set(weights)) != 1:
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for i, w in enumerate(weights):
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if weights.count(w) == 1:
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diff = w
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wrong_disc = node.aboves[i].name
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else:
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same = w
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proper_weight = DISCS[wrong_disc].weight + (same - diff)
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print "Proper weight of `{}`: {}".format(wrong_disc, proper_weight)
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sys.exit()
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BAD_WEIGHTS[node.name] = weights
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return sum(weights) + node.weight
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# Initialize the recursion, which will also find the solution.
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# Seed `BAD_WEIGHTS`
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program_weight(root)
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# Traverse from root until the offending disc is found
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bad_disc = root
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while True:
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for a in bad_disc.aboves:
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if a.name in BAD_WEIGHTS:
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bad_disc = a
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break
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else:
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break
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# Determine the correct weight of the child disc
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weights = BAD_WEIGHTS[bad_disc.name]
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for i, w in enumerate(weights):
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if weights.count(w) == 1:
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diff = w
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wrong_disc = bad_disc.aboves[i].name
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else:
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same = w
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proper_weight = DISCS[wrong_disc].weight + (same - diff)
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print "Proper weight of `{}`: {}".format(wrong_disc, proper_weight)