pull request from Michael Miller for Dev Prework (Project Euler #3,5,8)

problem03.rb

@@ -0,0 +1,22 @@
+require 'prime' #allows the program to use the prime class
+
+
+testNum = 600851475143 # number to get the primes of
+$primeFactors = [] # array for storing prime factors
+
+def getPrimeFactors(n)
+	i = 2 # i will be the divisor, which will start at 2 since all numbers are divisible by 1
+	while (i<=n) do
+		# if i is evenly divisible into the test number, see if it is a prime, and if so, push it into the prime array
+		if n%i == 0
+			if Prime.prime?(i)
+				$primeFactors.push(i)
+				n = n/i # make the test number the quotient of the found prime factor
+			end
+		end
+		i+=1
+	end
+end
+
+getPrimeFactors(testNum)
+puts "The prime factors of #{testNum} are #{$primeFactors}.\n The largest prime factor is #{$primeFactors.max}."

problem05.rb

@@ -0,0 +1,37 @@
+# takes an input of a min and max value to establish a range, as well as a start number 
+def getTestArray(min, max, startnumber)
+	$testArray = Array(min..max)
+	$number = startnumber
+end
+
+def testModulo(n, factor)
+	# n = number to start from
+	# factor = number to increase by
+	result=true
+
+		$testArray.each  { |i|
+			puts "#{n}/#{i}"
+			if n%i != 0
+				result = false
+				puts "#{n}/#{i} has a remainder - no good!"
+				break
+			end
+		}
+
+	if result == true
+		puts "Success!"
+		return true
+	else
+		$number += factor
+		puts "New number: #{$number}"
+		return false
+	end
+end
+
+getTestArray(1,20,232790000) #inputs 1-20 for the range and a large start number so the program does not take long to find the right number
+
+while testModulo($number, $testArray.max) == false do
+	testModulo($number, $testArray.max)	
+end
+
+puts "The smallest number that is a multiple of #{$testArray.min} thru #{$testArray.max} is #{$number}" 

problem08.rb

@@ -0,0 +1,70 @@
+a = %w{73167176531330624919225119674426574742355349194934
+96983520312774506326239578318016984801869478851843
+85861560789112949495459501737958331952853208805511
+12540698747158523863050715693290963295227443043557
+66896648950445244523161731856403098711121722383113
+62229893423380308135336276614282806444486645238749
+30358907296290491560440772390713810515859307960866
+70172427121883998797908792274921901699720888093776
+65727333001053367881220235421809751254540594752243
+52584907711670556013604839586446706324415722155397
+53697817977846174064955149290862569321978468622482
+83972241375657056057490261407972968652414535100474
+82166370484403199890008895243450658541227588666881
+16427171479924442928230863465674813919123162824586
+17866458359124566529476545682848912883142607690042
+24219022671055626321111109370544217506941658960408
+07198403850962455444362981230987879927244284909188
+84580156166097919133875499200524063689912560717606
+05886116467109405077541002256983155200055935729725
+71636269561882670428252483600823257530420752963450}
+
+b="" #empty string
+
+#concatenates each line of 'a' to make one long string, b
+a.each do |i|
+	b = b + i
+end
+
+num_digits = 5 #number of adjacent digits to scan
+products = [] #empty array to store the products
+position = 0 #variable to indicate at what position the scan is at during each iteration, starts at 0
+
+while position <= (b.length - num_digits)
+	has_zero = false #boolean to store whether a 0 has been found 
+	digits = [] #array to store the digits
+	count = position #variable to move up through the digits of each iteration
+	product = 1 #variable to store the product of each iteration, starts at 1 for each iteration
+
+	puts "- POSTION #{position} of #{b.length}"
+
+	for i in 0..(num_digits - 1)
+		digits[i] = b[count..count].to_i
+		if digits[i] == 0 
+			has_zero = true
+			break
+		else
+			count += 1
+		end
+	end
+
+	if has_zero
+		product = 0
+	else 
+		digits.each do |i|
+			product *= i
+		end
+	end
+	puts "product: #{product}"
+	products.push(product)
+	position += 1
+end
+
+
+if products.max == nil || products.max == products.min
+	puts "There is no maximum product in this number."	
+else
+	puts "The greatest product of #{num_digits} adjacent digits is #{products.max} at position #{products.rindex(products.max)} in the #{b.length} digit number."
+end
+
+