Day21

[CmdletBinding()]
Param(
    [string[]]
    $rules,
    [int]$loops=18
)

if (-not $rules) {
    $rules = gc .\day21.txt
    #$rules = "../.# => ##./#../...%.#./..#/### => #..#/..../..../#..#" -split "%"
}

class grid {
    [char[, ]]$items
    [int]$size
    grid ([int] $size) {
        $this.size = $size
        $this.items = New-Object "char[,]" $size, $size
    }
    grid ([int]$size, [string]$data) {
        $this.size = $size
        $this.items = New-Object "char[,]" $size, $size
        $chars = $data.ToCharArray()
        for ( $i = 0; $i -lt $chars.Count; $i++ ) {
            $x = 0
            $y= [system.math]::DivRem($i,$size,[ref]$x)
            $this.items[$x, $y] = $chars[$i]
        }
    }
    [grid]flipx(){
        $cs = for ( $y = 0; $y -lt $this.size; $y++ ) {
            for ( $x = ($this.size-1); $x -ge 0; $x-- ){
                $this.items[$x, $y]
            }
        }
        return [grid]::new($this.size,($cs-join''))
    }
    [grid]flipy(){
        $cs = for ( $y = ($this.size-1); $y -ge 0; $y-- ) {
            for ( $x = 0; $x -lt $this.size; $x++ ){
                $this.items[$x, $y]
            }
        }
        return [grid]::new($this.size,($cs-join''))
    }
    [grid]flipxy(){
        $cs = for ( $y = ($this.size-1); $y -ge 0; $y-- ) {
            for ( $x = ($this.size-1); $x -ge 0; $x-- ){
                $this.items[$x, $y]
            }
        }
        return [grid]::new($this.size,($cs-join''))
    }
    [grid]rotateCW(){
        $cs = for ( $y = ($this.size-1); $y -ge 0; $y-- ) {
            for ( $x = ($this.size-1); $x -ge 0; $x-- ){
                $this.items[(($this.size-1)-$y), $x]
            }
        }
        return [grid]::new($this.size,($cs-join''))
    }
    [string]toStringGrid(){
        $cs = for ( $y = 0; $y -lt $this.size; $y++ ) {
            for ( $x = 0; $x -lt $this.size; $x++ ){
                $this.items[$y, $x]
            }
            "`n"
        }
        return ($cs -join '')
    }
    [string]toString(){
        $cs = for ( $y = 0; $y -lt $this.size; $y++ ) {
            for ( $x = 0; $x -lt $this.size; $x++ ){
                $this.items[$y, $x]
            }
            #"`n"
        }
        return ($cs -join '')
    }
    static[grid]join([grid[]] $grids){
        $gs = $grids[0].size
        $gridss = [system.math]::Sqrt( $grids.Count )
        $s = $gs * $gridss
        $newgrid = [grid]::new($s)
        for ( $i = 0; $i -lt $grids.Count; $i++ ) {
            $gridx = 0
            $gridy= [system.math]::DivRem($i,$gridss,[ref]$gridx)
            for ( $j = 0; $j -lt $gs*$gs; $j++ ){
                $x = 0
                $y= [system.math]::DivRem($j,$grids[$i].size,[ref]$x)
                $newgrid.items[
                    ( ($gridx * $gs ) + $x ),
                    ( ($gridy * $gs ) + $y )
                ] = $grids[$i].items[$x,$y]
            }
        }
        return $newgrid
    }
    [grid[]]split([int]$size){
        $gs = $size
        $gridss = $this.size / $size
        $newgrids = for ( $i = 0; $i -lt $gridss*$gridss; $i++ ) {
            $gridx = 0
            $gridy= [system.math]::DivRem($i,$gridss,[ref]$gridx)
            $childgrid = [grid]::new($gs)
            for ( $j = 0; $j -lt $gs*$gs; $j++ ){
                $x = 0
                $y= [system.math]::DivRem($j,$gs,[ref]$x)
                $childgrid.items[$x,$y] = $this.items[
                    ( ($gridx * $gs ) + $x ),
                    ( ($gridy * $gs ) + $y )
                ]
            }
            $childgrid
        }
        return $newgrids
    }
}

$subs = @{}

$rules | % {
    $a=$_ -replace '/','' -split ' => '
    $subs[$a[0]] = $a[1]
}

#start
$newgrid = [grid]::new(3,'.#...####')

$script:cache = @{}

function calc1 {
    Param(
        $subs,
        [grid]$grid
    )
    $split = $false
    $gs=$null
    if ($grid.size % 2 -eq 0){
        $gs = $grid.split(2)
        $split = $true
    } elseif ($grid.size % 3 -eq 0) {
        $gs = $grid.split(3)
        $split = $true
    } else {
        Write-Error "Can't split grid anymore."
    }
    if ($split){
        $newgrids = $gs | %{
            $str = $_.toString()
            if ( $script:cache[ $str ] ){
                $script:cache[ $str ]
            } else {
                $patterns = @(
                    $str
                    $_.flipx().ToString() #flipx
                    $_.flipy().ToString() #flipy
                    $_.flipxy().ToString() #rot180
                    $_.rotateCW().ToString() # rot90
                    $_.rotateCW().flipx().ToString() #flipxrot90
                    $_.rotateCW().flipy().ToString() #flipyrot90
                    $_.rotateCW().flipxy().ToString() # rot270
                )
                $reps = $patterns | %{
                    if ($subs[$_.ToString()]){
                        $size = [system.math]::Sqrt( $subs[$_.ToString()].length )
                        [grid]::new($size,$subs[$_.ToString()])
                    }
                }
                $return = if ($reps.Count -gt 1){
                    $reps[0]
                } else {
                    $reps
                }
                $patterns | %{
                    if(-not ($script:cache[$_])){
                        $script:cache[$_]=$return
                    }
                }
                $return
            }
        }
        return [grid]::join($newgrids)
    }
}

1..$loops| %{
    $time = Measure-Command {
        $newgrid = calc1 -subs $subs -grid $newgrid
    }
    "$_ : $($time.tostring())"
}
#>
($newgrid.toString() -replace "[.]",'').length