Time- Haben

lib/array_intersection.rb

@@ -1,3 +1,19 @@
-def intersection(list1, list2)
-  raise NotImplementedError, "Intersection not implemented"
-end
+#Design and implement a method that takes two integer arrays with unique 
+#values and returns their intersection in a new array.
+
+def intersection(array1, array2)
+  intersection = []
+  new_hash = {}
+
+  array1.each do |number1|
+    new_hash[number1] = 1
+  end
+
+  array2.each do |number2|
+    if new_hash[number2] == 1
+      intersection << number2
+    end
+  end
+  return intersection
+end
+

lib/palindrome_permutation.rb

@@ -1,4 +1,24 @@
 
-def palindrome_permutation?(string)
-  raise NotImplementedError, "palindrome_permutation? not implemented"
-end
+# Write a method which takes a string as an argument and returns 
+# true if the letters could be re-arranged into a palindrome.
+
+ def palindrome_permutation?(string)
+    pal_per = {}
+
+    string.chars.each do |letter|
+      if pal_per[letter] == nil
+         pal_per[letter] = 1
+      else
+        pal_per[letter] += 1
+      end
+    end
+
+    odd_count = 0
+    pal_per.each do |letter, count|
+      if count % 2 == 1
+        odd_count += 1
+      end
+    end
+    return odd_count <= 1
+ end
+

lib/permutations.rb

@@ -1,4 +1,37 @@
+# Write a method which will take two strings as arguments 
+# and returns true if one string is a permutation of the other.
 
 def permutations?(string1, string2)
-  raise NotImplementedError, "permutations? not implemented"
-end
+  first_hash = {}
+  second_hash = {}
+
+  string1.chars.each do |letter|
+    first_hash[letter] = 0
+  end
+
+  string1.chars.each do |letter|
+   first_hash[letter] += 1
+  end
+
+  string2.chars.each do |letter|
+    second_hash[letter] = 0
+  end
+
+  string2.chars.each do |letter|
+    second_hash[letter] += 1
+   end
+
+   first_hash.each do |key, value|
+    if second_hash.has_key?(key) 
+      if second_hash[key] == value
+
+      else
+        return false
+      end
+    else
+      return false
+    end
+  end
+  return true
+end
+

test/palindrome_permutation_test.rb

@@ -1,6 +1,6 @@
 require_relative "test_helper"
 
-xdescribe "palindrome_permutation?" do
+describe "palindrome_permutation?" do
   it "will work for hello" do
     expect(palindrome_permutation?("hello")).must_equal false
   end

test/permutations_test.rb

@@ -1,6 +1,6 @@
 require_relative "test_helper"
 
-xdescribe "permutations?" do
+describe "permutations?" do
   it "returns true for empty string" do
     expect(permutations?("", "")).must_equal true
   end