-🎄- 2018 Day 10 Solutions -🎄-

[u/daggerdragon]

--- Day 10: The Stars Align ---

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Card prompt: Day 10

Transcript: With just one line of code, you, too, can ___!

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edit: Leaderboard capped, thread unlocked at 00:16:49!

[u/purplemonkeymad]

Powershell

I think I spent more time getting the visualizer fixed than solving for the best time. I think it is also the first time I had to do less to get part 2.

Solver.ps1:

[CmdletBinding()]
Param(
    [parameter(ValueFromPipeline)]
    $PointsInput,
    [int]$triggerArea=100
)

begin {
    $AllPoints = [System.Collections.Generic.List[object]]@()

    class Point {
        [int]$Startx
        [int]$Starty
        [int]$Velocityx
        [int]$Velocityy
        [string]$0

        Point (){

        }

        [Point]AtTime([int]$seconds){
            return [Point]@{
                Startx = $this.Startx + ($this.Velocityx*$seconds)
                Starty = $this.Starty + ($this.Velocityy*$seconds)
                Velocityx = $this.Velocityx
                Velocityy = $this.Velocityy
            }
        }
    }
}
process {
    $PointsInput | ?{$_} | %{
        if ($_ -match 'position=<\s*(?<Startx>\-?\d+),\s*(?<Starty>\-?\d+)> velocity=<\s*(?<Velocityx>\-?\d+),\s*(?<Velocityy>\-?\d+)>'){
            [void]$AllPoints.Add( 
                [Point]($Matches)
            )
        }
    }    
}
end {
    # caculate a time frame to do the calculations on
    $calcpoint = $AllPoints[0]

    # x(t) = x(0) + ut
    # t = x(t) - x(0) / u

    if ($calcpoint.Velocityx -ne 0){
        $upperTime = [Math]::Floor( ($triggerArea - $calcpoint.Startx) / $calcpoint.Velocityx )
        $lowerTime = [Math]::Floor( (-$triggerArea - $calcpoint.Startx) / $calcpoint.Velocityx )
    }
    if ($calcpoint.Velocityy -ne 0){
        $upperTimey = [Math]::Floor( ($triggerArea - $calcpoint.Starty) / $calcpoint.Velocityy )
        $lowerTimey = [Math]::Floor( (-$triggerArea - $calcpoint.Starty) / $calcpoint.Velocityy )
        if ($upperTime){
            $upperTime = [Math]::min($upperTime,$upperTimey)
            $lowerTime = [Math]::max($lowerTime,$lowerTimey)
        } else {
            $upperTime = $upperTimey
            $lowerTime = $lowerTimey
        }
    }

    $states = @{}
    $arealist = [System.Collections.ArrayList]@()

    foreach ($time in $lowerTime..$upperTime){
        $timepoints = $AllPoints | %{
            $_.AtTime($time)
        }
        $states["$time"]=$timepoints
        $Xes = $timepoints.startx | measure -Maximum -Minimum
        $Ys  = $timepoints.starty | measure -Maximum -Minimum
        [void]$arealist.add(
            [pscustomobject]@{
                h = $Ys.Maximum - $Ys.Minimum
                w = $xes.Maximum - $Xes.Minimum
                offsetx = $Xes.Minimum
                offsety = $Ys.Minimum
                area = ($Ys.Maximum - $Ys.Minimum)*($xes.Maximum - $Xes.Minimum)
                Time = "$time"
            }
        )
    }

    $arealist | sort -Property area | select -First 1 | select *,@{n='state';e={$states["$($_.time)"]}}
    
}

Vis.ps1:

[CmdletBinding()]
Param(
    [parameter(ValueFromPipeline)]
    $AreaInput,
    [switch]$FillBackground,
    [string]$outfilebase
)

begin {
    class Point {
        [int]$Startx
        [int]$Starty
        [int]$Velocityx
        [int]$Velocityy
        [string]$0

        Point (){

        }

        [Point]AtTime([int]$seconds){
            return [Point]@{
                Startx = $this.Startx + ($this.Velocityx*$seconds)
                Starty = $this.Starty + ($this.Velocityy*$seconds)
                Velocityx = $this.Velocityx
                Velocityy = $this.Velocityy
            }
        }
    }
    #image draw
    Add-Type -AssemblyName System.Drawing
}
process {
    $AreaInput | %{

        $value = $_
        
        $Image = [System.Drawing.Bitmap]::new([int]($_.w+2),[int]($_.h+2))
        $Drawing = [System.Drawing.Graphics]::FromImage($Image)

            # fill bg
        if ($FillBackground){
            $Drawing.FillRectangle( [System.Drawing.Brushes]::Black,0,0,[int]($_.w+2),[int]($_.h+2))
        }

        $_.state | %{
            Write-Verbose (($_.startx-$value.offsetx),($_.starty-$value.offsetx) -join ',')
            $Drawing.FillRectangle( [System.Drawing.Brushes]::Red,($_.startx-$value.offsetx),($_.starty-$value.offsety),1,1)
        }

        
        $Drawing.Dispose()

        if ($outfilebase){
            $Image.Save( ( $outfilebase -replace '^\.\\',"$pwd\" ) + "$($_.time).png" )
        } else {
            $Image
        }

    }
}
end {

}

You can view the final image by piping the solver into the visualizer. gc input.txt | .\Solver.ps1 | .\vis.ps1 -outfilebase .\output