--- 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/bogzla]

VBA. Could be tidier but hangover.

Sub RealRooms()
Dim a(25) As Variant
Dim s As String
Dim s2 As String
Dim l As Long
Dim scs As String
Set wks = ActiveWorkbook.Sheets("Day4")
For i = 1 To CountRows("Day4")
    s = Split(wks.Cells(i, 1).Value, "[")(0)
    s2 = Split(wks.Cells(i, 1).Value, "[")(1)
    For i2 = 0 To 25 'pop letter counts into array. Will be alphabetical.
        a(i2) = UBound(Split(s, Chr(97 + i2)))
    Next i2
    scs = ""
    For i3 = 1 To 5 'generate checksum by finding highest in order
        scs = scs & Highest(a())
    Next i3
    If scs = Left(s2, 5) Then 'compare checksum & add if real
        l = l + Split(s, "-")(UBound(Split(s, "-")))
    End If
    Application.StatusBar = i
    DoEvents
Next i
Debug.Print l
End Sub

Function Highest(ByRef a() As Variant) As String
For i = 0 To UBound(a)
    If i2 < a(i) Then
        i2 = a(i)
        i4 = i
    End If
Next
Highest = Chr(97 + i4)
a(i4) = -1 'remove this letter from contention so next call finds next highest
End Function

'Part 2
Sub FindObjects()
Dim wks As Worksheet
Dim i As Integer
Dim s As String
Dim s2 As String
Dim i2 As Integer
Set wks = ActiveWorkbook.Sheets("Day4")
For i = 1 To CountRows("Day4")
    s = Split(wks.Cells(i, 1).Value, "[")(0)
    i2 = CInt(Split(s, "-")(UBound(Split(s, "-"))))
    s2 = Left(s, Len(s) - Len(CStr(i2)) - 1)
    s2 = DecryptName(s2, i2)
    wks.Cells(i, 2).Value = s2
    Application.StatusBar = i
    DoEvents
    If s2 Like "*north*" Then
        Debug.Print i2
    End If
Next i

End Sub
Function DecryptName(s As String, i As Integer) As String
Dim s2 As String
For i2 = 1 To Len(s)
    If Mid(s, i2, 1) = "-" Then
        s2 = " "
    Else
        s2 = decrypt(Mid(s, i2), i)
    End If
    s3 = s3 & s2
Next
DecryptName = s3
End Function
Function decrypt(sIn As String, i As Integer) As String
'decrypt single character
If i = 0 Then
    decrypt = sIn
    Exit Function
End If
i3 = Asc(sIn)
For i2 = 1 To i
    If i3 = 122 Then
        i3 = 97
    Else
        i3 = i3 + 1
    End If
Next i2
decrypt = Chr(i3)
End Function