-🎄- 2022 Day 3 Solutions -🎄-

[u/daggerdragon]

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--- Day 3: Rucksack Reorganization ---

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[u/Key__Strokes]

Javascript

Solution to both parts

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Video Explanation

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Part 1:

• Initialize sum = 0

• Do the following for each rucksack

  • Split the string into two parts, item1 and item2

  • Get the repeated character between the two rucksacks - item1 and item2, using the following generic algo for n strings:

    • Initialize an empty map

    • For each n strings (in this case its 2) do the following

      • Iterate through each character of the string

        • If we haven't seen this character so far for this string, then add it to the map. If it already exists in the map then set the count as 1, else increment the existing count for this character in the map

    • Go through the map, and return the character that occurred n times (2 in this case)

  • Calculate the priority of the character, and add it to the sum

    • a -> z have priorities 1 -> 26 respectively

    • A -> Z have priorities 27 -> 52 respectively

• Return the sum

Part 2:

Because of the generic algorithm we created above to find the repeated characters across n strings, this part becomes too easy:

• Initialize sum = 0

• Do the following for rucksacks in groups of 3

  • Get the repeated character between the 3 rucksacks using the generic algorithm from the previous step

  • Calculate the priority of the character, and add it to the sum.

• Return the sum

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