reddit-dailyprogrammer-235.ps1

# URI: https://www.reddit.com/r/dailyprogrammer/comments/3nkanm/20151005_challenge_235_easy_ruthaaron_pairs/
# Ruth-Aaron Pairs.
function GetRuthAaronPairs {
  
  # GetSumOfPrimeFactors: Calculates and sums the prime factors for a given number.
  function GetSumOfPrimeFactors {
    param ([int]$Number)
    
    $sum = 0
    $current = $Number
    for ( $i = 2; $current -gt 1 ; $i++ ) {
      if ( $current % $i -eq 0 ) {
        $sum += $i
        while ( $current % $i -eq 0 ) {
          $current = $current/$i
        }
      }
    }
    return $sum
  }
  
  $NumberOfPairs = [int](Read-Host "Number of pairs")
  $pairs = @()
  for ($i=0; $i -lt $numberOfPairs; $i++) {
    $maybePair = Read-Host "Pair"
    $firstNumber, $secondNumber = $maybePair -replace '\(|\)','' -split ','
    if (!$firstNumber -or !$secondNumber) {
      throw "One or both numbers are missing from this pair."
    }
    $dummyInt = 0
    if (![Int]::TryParse($firstNumber, [ref]$dummyInt) -or ![Int]::TryParse($secondNumber, [ref]$dummyInt)) {
      throw "One of both of the numbers in this pair are invalid."
    }
    if ($secondNumber-$firstNumber -ne 1) {
      throw "[$firstNumber] and [$secondNumber] do not compose a Ruth-Aaron pair."
    }
    $pairs += ,@($firstNumber,$secondNumber)
  }
  
  write-verbose "Pairs: $pairs"
  
  foreach ($pair in $pairs) {
    $firstNumber = $pair[0]
    $secondNumber = $pair[1]
    write-host "($firstNumber`,$secondNumber) " -NoNewLine
    if ( (GetSumOfPrimeFactors($firstNumber)) -ne (GetSumOfPrimeFactors($secondNumber)) ) {
      write-host "NOT VALID"
    }
    else {
      write-host "VALID"
    }
  }
}