Advent_of_code_2017_Day1.ps1

function Day1 {
param ($sequence, $offset)
	[int]$sum = 0
	for ($i=0; $i -lt $sequence.Length; $i++){
		$k = $i + $offset
		if ($k -ge $sequence.Length){
			$k = $k - $sequence.Length
		}

		if ([int]$sequence[$i] -eq [int]$sequence[$k]){			
			$sum += [int][string]$sequence[$i]
		}	
	}
	$sum
}
$sequence = '1212'
#Day 1-1
Day1 -sequence $sequence -offset 1
#Day 1-2
Day1 -sequence $sequence -offset $($sequence.Length / 2)