prime factors

12meses12katas · Aug 2, 2011 · 5b82cfa · 5b82cfa
1 parent 391e632
commit 5b82cfa
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Showing 2 changed files with 8 additions and 3 deletions.
diff --git a/lantoli/lib/primefactors.rb b/lantoli/lib/primefactors.rb
@@ -1,3 +1,5 @@
+require 'mathn'
+
 class PrimeFactors
 
   def self.generate number
@@ -13,7 +15,7 @@ def self.generate number
           candidate = (candidate==2) ? 3 : candidate + 2 # performance tip: only odd candidates
         end
       end
-      factors << number unless number <= limit # performance tip
+      factors << number unless number <= limit # performance tip - square root
       factors
   end
 
@@ -23,7 +25,7 @@ class Integer
   def factor_of? number
     number % self == 0
   end
- 
+
   def sqrt
     Math.sqrt(self).to_i
   end

diff --git a/lantoli/spec/primefactors_spec.rb b/lantoli/spec/primefactors_spec.rb
@@ -12,7 +12,10 @@
     288 => [2,2,2,2,2,3,3],
     24 => [2,2,2,3],
     100 => [2,2,5,5],
-    123456789 => [3,3,3607,3803]  
+    123456789 => [3,3,3607,3803],
+    123456791 => [123456791],
+    1234567927 => [1234567927],
+    2469135854 => [2,1234567927]
   }
 
   primeTests.each do | number, factors|