Day 16: Reindeer Maze

Megathread guidelines

  • Keep top level comments as only solutions, if you want to say something other than a solution put it in a new post. (replies to comments can be whatever)
  • You can send code in code blocks by using three backticks, the code, and then three backticks or use something such as https://topaz.github.io/paste/ if you prefer sending it through a URL

FAQ

  • @[email protected]
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    fedilink
    313 hours ago

    prev_nodes[neighbor].append(node)

    I think you’re adding too many neighbours to the prev_nodes here potentially. At the time you explore the edge, you’re not yet sure if the path to the edge’s target via the current node will be the cheapest.

    • @[email protected]
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      fedilink
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      edit-2
      4 hours ago

      Good catch! IIRC, only when a node is selected from the min heap can we guarantee that the cost to that node will not go any lower. This definitely seems like a bug, but I still got the correct answer for the samples and my input somehow ¯\_(ツ)_/¯