Space - Diana

lib/array_intersection.rb

@@ -1,3 +1,25 @@
 def intersection(list1, list2)
-  raise NotImplementedError, "Intersection not implemented"
+  lookup_hash = {}
+
+  if list1.length < list2.length
+    list1.each do |num|
+      lookup_hash[num] = true
+    end
+
+    intersection_array = list2.map do |num|
+      num if lookup_hash[num]
+    end
+
+    return intersection_array.compact
+  else
+    list2.each do |num|
+      lookup_hash[num] = true
+    end
+
+    intersection_array = list1.map do |num|
+      num if lookup_hash[num]
+    end
+
+    return intersection_array.compact
+  end
 end

lib/palindrome_permutation.rb

@@ -1,4 +1,25 @@
 
 def palindrome_permutation?(string)
-  raise NotImplementedError, "palindrome_permutation? not implemented"
+  lookup_hash = {}
+  string.each_char do |letter|
+    lookup_hash[letter] = 0
+  end
+
+  string.each_char do |letter|
+    if lookup_hash[letter]
+      lookup_hash[letter] += 1
+    end
+  end
+
+  number_of_odd = 0
+  lookup_hash.each_value do |letter|
+    number_of_odd += 1 if letter.odd?
+  end
+
+  if number_of_odd > 1
+      return false
+    else
+      return true
+  end
+
 end

lib/permutations.rb

@@ -1,4 +1,21 @@
-
 def permutations?(string1, string2)
-  raise NotImplementedError, "permutations? not implemented"
+  return false if string1.length != string2.length
+
+  lookup_hash = {}
+  string1.each_char do |letter|
+    lookup_hash[letter] = 0
+  end
+
+  string2.each_char do |letter|
+    if lookup_hash[letter]
+      lookup_hash[letter] = true
+    end
+  end
+
+  puts lookup_hash
+  if lookup_hash.value?(0) 
+    return false
+  else
+    return true
+  end
 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