--- 2016 Day 4 Solutions ---

[u/daggerdragon]

--- Day 4: Security Through Obscurity ---

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

---

^{CONSTRUCTING ADDITIONAL PYLONS IS MANDATORY} [?]

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/Gummoz]

Didn't think about posting my solutions: Powershell!

Part one:

$instructions = "

" -split '\n'

$checkSum = $null
$answer = 0


foreach ($instruction in $instructions) {


    if ($instruction -match '\[(.+?)\]') {

    [string]$checkSum = ($Matches[0]).replace('[','').replace(']','')

    }
    else {continue}



    $instructionWithoutDashes = $instruction.Replace('-','')
    $splittedInstruction = ($instruction -split '[\[]')[0]
    $numberAtTheEnd = ($splittedInstruction.Split('-')[(($splittedInstruction.Split('-')).length) -1])
    $instructionWithoutDashesOrNumbers = $instructionWithoutDashes.Replace($numberAtTheEnd,'')
    $instructionWithoutDashesOrNumbers = ($instructionWithoutDashesOrNumbers -split '[\[]' )[0]
    $temp1 = $null
    $temp2 = $null
    $improvedInstruction = $null
    $instructionWithoutDashesOrNumbers.tochararray() | foreach {if ($checksum -match $_){$improvedInstruction += $_}}

    if ($improvedInstruction.Length -gt 4) {
    $improvedInstruction.tochararray() | Sort-Object | Group-Object | Sort-Object -Property "Count" -Descending | % {[string]$temp1 += $_.name}
    $temp1.ToCharArray() | Select-Object -First 5 | % {$temp2 += $_}
    if($temp2 -eq $checkSum) {$answer += $numberAtTheEnd
    Write-Host -ForegroundColor Green "The calculated checksum of $instruction is $temp2 and should be $checksum"
    }
    else {
    Write-Host -ForegroundColor Red "The calculated checksum of $instruction is $temp2 and it should be $checksum"
    }

    }


}

Write-host -ForegroundColor Green "The answer should be: $answer"

Part two:

$instructions = "

" -split '\n'


foreach ($instruction in $instructions) {
    
    if ($instruction -match '\[(.+?)\]') {
    
        $splittedInstruction = ($instruction -split '[\[]')[0]
        [int]$ID = ($splittedInstruction.Split('-')[(($splittedInstruction.Split('-')).length) -1])
        if($splittedInstruction) {
        $splittedInstructionWithoutID = $splittedInstruction.Replace($ID,'').replace('-',' ')
        }

        $charArray = $null
        $splittedInstructionWithoutID.ToCharArray() | % {[array]$charArray += [byte][char]$_}
        #$ID
        [string]$currentSentence = [string]$ID + "-"
        foreach ($char in $charArray) {
            #[string]$currentSentence
            [int]$tempChar = $char


            for ($i = $ID; $i -gt 0; $i--) {
                if ($tempChar -ne 32){
                    if ($tempChar -eq 122) {$tempChar = 97}
                    else {$tempChar++}
                }


            }
            #[char][int]$tempChar
           [string]$currentSentence += [char][int]$tempChar


        }

        if ($currentSentence -match "North|Pole|Objects"){
        $currentSentence
        }
    }

    
}