Project Euler Problem 1 PowerShell Version

Project Euler Problem 1.ps1

#単純に加算
$sum = 0
foreach ($i in 1..999)
{
    if (($i % 3) -eq 0)
    {
        $sum += $i
    }
    elseif (($i % 5) -eq 0)
    {
        $sum += $i
    }
}
Write-Host $sum
 
#等差数列の和
$sum = 0
#初項, 公差
foreach($a in @(3, 5, 15))
{
    $n = [math]::floor(999 / $a) #項数
    $l = $n * $a                 #末項 a＋(n－1)d
 
    switch ($a)
    {
        3       {$sum += (($a + $l) * $n / 2)}
        5       {$sum += (($a + $l) * $n / 2)}
        default {$sum -= (($a + $l) * $n / 2)}
    }
}
Write-Host $sum