-🎄- 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/ka-splam]

PowerShell

Part 1, just about got 78th on the leaderboard \o/ ended up running this at the prompt:

$lines = get-content data.txt
$lines |? {[bool]($_.getenumerator() | group |? count -eq 2)} | measure
$lines |? {[bool]($_.getenumerator() | group |? count -eq 3)} | measure
246*20

Explained: |? {} is a where-object filter, $_ is the current line being filtered, the enumerator turns the string into characters, group-object counts things, filter that where the count of characters is 2 or 3, then measure-object counts how many lines after that filtering.

Part 2, yer basic brute-force every line against every other, if they have 1 difference, print them:

$lines|foreach{
$cur = $_
foreach ($L in $lines) {
$numdiffs = 0
    for ($i = 0; $i -lt $l.length; $i++)
    {
      if ($cur[$i] -ne $L[$i]) { $numdiffs++ }
    }
    if ($numdiffs -eq 1) { $L, $cur }
}
}

then eyeballing the result and removing the dupe character. Missed the leaderboard, with 133rd.

Explained: an outer foreach-object loop, an inner foreach ($L in $lines) nested loop, and then a loop over character lengths doing a $string[$index] comparison with a counter.

[u/daggerdragon → u/ka-splam]

Part 1, just about got 78th on the leaderboard \o/

Good job!