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Discussion on: Understanding Time Complexity with the First Puzzle of Advent of Code

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Replies for: Or almost happy 😂 Now I realized that there's no need to read all of the values at all. The file can be read line by line and the read values can ...

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annisalli profile image
Anniina Sallinen • • Edited

Interesting! I'm not familiar with Golang, but googled and read that you can check the membership with

exists := set["Foo"]
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If you know which number you're looking for (calculating 2020 - x = y), and I read the example above correctly, couldn't you just

exists := set[y]
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Do you need to save the read values to a map, I'm not so sure? 🤔

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Laura Vuorenoja •

Yes, I mean that I use the map structure instead of set (I think go does not have sets 🤔 ). Let me paste here my pseudolike code:

func findValue: int
  cache := new key-value-storage
  for line = read-next-line from file:
    nbr := convert line to nbr
    want := 2020 - nbr
    if cache[want]:
      return want * nbr
    cache[nbr] = nbr
  return 0
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So I mean "saving to a map" this line cache[nbr] = nbr. Of course the value could be anything, only the key counts ☺️

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Anniina Sallinen • • Edited

Ohh yeah now I see 😊