From b8f7235bd2a94116793a7dd4f49ea15b5115deca Mon Sep 17 00:00:00 2001
From: Valerie <val.conklin@gmail.com>
Date: Mon, 9 May 2016 18:25:39 -0700
Subject: [PATCH] Finished recursive hamming yaaay

---
 hamming.rb      | 29 +++++++++++++++++++++++++++++
 hamming_test.rb | 14 --------------
 2 files changed, 29 insertions(+), 14 deletions(-)
 create mode 100644 hamming.rb

diff --git a/hamming.rb b/hamming.rb
new file mode 100644
index 0000000..daa7b0c
--- /dev/null
+++ b/hamming.rb
@@ -0,0 +1,29 @@
+class Hamming
+
+  def self.compute(strand1, strand2)
+
+    raise ArgumentError if strand1.length != strand2.length
+
+    # base case
+    if strand1.empty? || strand2.empty?
+      return 0
+    end
+
+    # gets last element of array-type strand1 and strand2
+    nuc1 = strand1.split(//).pop
+    nuc2 = strand2.split(//).pop
+
+    adder = 0
+    if nuc1 != nuc2
+      adder = 1
+    end
+
+    # removes the final letter so string ending in next letter for comparison can be passed through recursion
+    strand1.chop!
+    strand2.chop!
+
+    return adder + self.compute(strand1, strand2)
+
+  end
+
+end
diff --git a/hamming_test.rb b/hamming_test.rb
index 2d1f9d7..0ddf0a1 100644
--- a/hamming_test.rb
+++ b/hamming_test.rb
@@ -4,72 +4,58 @@
 
 class HammingTest < Minitest::Test
   def test_identical_strands
-    skip
     assert_equal 0, Hamming.compute('A', 'A')
   end
 
   def test_long_identical_strands
-    skip
     assert_equal 0, Hamming.compute('GGACTGA', 'GGACTGA')
   end
 
   def test_complete_distance_in_single_nucleotide_strands
-    skip
     assert_equal 1, Hamming.compute('A', 'G')
   end
 
   def test_complete_distance_in_small_strands
-    skip
     assert_equal 2, Hamming.compute('AG', 'CT')
   end
 
   def test_small_distance_in_small_strands
-    skip
     assert_equal 1, Hamming.compute('AT', 'CT')
   end
 
   def test_small_distance
-    skip
     assert_equal 1, Hamming.compute('GGACG', 'GGTCG')
   end
 
   def test_small_distance_in_long_strands
-    skip
     assert_equal 2, Hamming.compute('ACCAGGG', 'ACTATGG')
   end
 
   def test_non_unique_character_in_first_strand
-    skip
     assert_equal 1, Hamming.compute('AGA', 'AGG')
   end
 
   def test_non_unique_character_in_second_strand
-    skip
     assert_equal 1, Hamming.compute('AGG', 'AGA')
   end
 
   def test_large_distance
-    skip
     assert_equal 4, Hamming.compute('GATACA', 'GCATAA')
   end
 
   def test_large_distance_in_off_by_one_strand
-    skip
     assert_equal 9, Hamming.compute('GGACGGATTCTG', 'AGGACGGATTCT')
   end
 
   def test_empty_strands
-    skip
     assert_equal 0, Hamming.compute('', '')
   end
 
   def test_disallow_first_strand_longer
-    skip
     assert_raises(ArgumentError) { Hamming.compute('AATG', 'AAA') }
   end
 
   def test_disallow_second_strand_longer
-    skip
     assert_raises(ArgumentError) { Hamming.compute('ATA', 'AGTG') }
   end
 end