2020-12-07 06:29:07 +00:00
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Day 7 Notes
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+--------+
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| Part 1 |
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+--------+
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$ elixir day7part1.exs
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142
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Thoughts:
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2020-12-08 03:39:29 +00:00
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First parse the input to a map of node => children, representing the requirement tree.
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2020-12-07 06:29:07 +00:00
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The question is to find the ancestors, so invert the tree.
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Use MapSet to avoid duplicates.
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Don't need the child count, but keep it around just in case.
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+--------+
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| Part 2 |
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+--------+
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$ elixir day7part2.exs
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10219
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Thoughts:
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Good job I kept the child count around.
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Don't need the inverted tree anymore, but can use the uninverted tree from part 1.
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Just walk the tree counting the children as we go.
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+------------------+
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| Overall Thoughts |
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+------------------+
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🎄 Trees 🎄
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Wondering if my use of MapSet for the inverted tree was overkill, simpler way?
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I *think* I got the fundamental idea of this one, rather than just hacking together whatever works,
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but seeing the other answers will be the judge of that :-)
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2020-12-07 16:49:07 +00:00
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** Update **
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I should have said DAG rather than tree, as each node can have multiple parents.
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