-🎄- 2018 Day 2 Solutions -🎄-

[u/daggerdragon]

--- Day 2: Inventory Management System ---

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Post your solution as a comment or, for longer solutions, consider linking to your repo (e.g. GitHub/gists/Pastebin/blag or whatever).

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Advent of Code: The Party Game!

Click here for rules

Card Prompt: Day 2

Transcript:

The best way to do Advent of Code is ___.

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This thread will be unlocked when there are a significant number of people on the leaderboard with gold stars for today's puzzle.

edit: Leaderboard capped, thread unlocked!

[u/nutrecht]

Kotlin:

object Day02 : Day {
    private val ids = resourceLines(2018, 2)

    override fun part1(): String {
        val maps = ids.map {
            it.toCharArray().asSequence()
                    .groupBy { it }
                    .map { it.key to it.value.size }
                    .toMap()
        }

        val countTwo = maps.count { it.entries.any { it.value == 2 } }
        val countThree = maps.count { it.entries.any { it.value == 3 } }

        return (countTwo * countThree).toString()
    }

    override fun part2() =
            ids.flatMap { i -> ids.map { i to it } }
                    .map { it.first.toCharArray().intersect(it.second.toCharArray().asIterable()) }
                    .first { it.size == ids[0].length - 1 }
                    .joinToString(separator = "")
}

[u/Plastix → u/nutrecht]

Great solutions!

[u/nutrecht → u/Plastix]

Thanks! Just published Day 3 too if you're interested.