Space - Hala

lib/array_intersection.rb

@@ -1,3 +1,45 @@
+## Array Intersection
+
+# Design and implement a method that takes two integer arrays with unique values and returns their intersection in a new array.
+
+# For example:
+
+# ```
+# intersection([2, 3, 4], [4, 5, 6]) => [4]
+# intersection([50, 43, 25, 72], [25, 36, 43, 50, 80]) => [50, 25, 43]
+# intersection([9, 30, 42], [56, 34, 90, 32]) => []
+# ```
+
+
+
 def intersection(list1, list2)
-  raise NotImplementedError, "Intersection not implemented"
+  shortlist = []
+  longest = []
+  if list1.length < list2.length
+    shortlist = list1
+    longest = list2
+  else 
+    shortlist = list2
+    longest = list1
+  end
+
+  hash = {}
+  shortlist.each do |item|
+  if 
+    longest.include?(item)
+      hash[item] = true
+    else 
+      hash[item] = false
+    end 
+  end
+
+  list3 = []
+  hash.keys.each do |key|
+    if 
+      hash[key] == true
+      list3<< key
+    end
+  end
+
+  return list3
 end

lib/palindrome_permutation.rb

@@ -1,4 +1,27 @@
+## Could Be A Palindrome
+
+# Write a method which takes a string as an argument and returns true if the letters could be re-arranged into a palindrome.
+
+# ```
+# palindrome_permutation?("hello") => false
+# palindrome_permutation?("carrace") => true # because racecar is a palindrome
+# ```
+
 
 def palindrome_permutation?(string)
-  raise NotImplementedError, "palindrome_permutation? not implemented"
+  count = {}
+  x = 0
+    string.each_char do |char|
+      count[char]= string.count(char)
+    end
+    count.keys.each do |key|
+      if count[key]%2 != 0
+        x +=1
+      end
+    end
+    if x == 0 || x == 1
+      return true
+    else 
+      return false
+    end
 end

lib/permutations.rb

@@ -1,4 +1,46 @@
 
-def permutations?(string1, string2)
-  raise NotImplementedError, "permutations? not implemented"
+## Check Permutations
+
+# Write a method which will take two strings as arguments and returns true if one string is a permutation of the other.
+
+# ```
+# permutations?("hello", "ehllo") => true
+# permutations?("pasta", "atsap") => true
+# permutations?("Pizza", "Pasta") => false
+# permutations?("", "") => true
+# ```
+
+
+def permutations?(string1, string2) 
+  hash = {}
+  if string1.length == string2.length
+    string2.each_char do |char|
+      if string1.include?(char)
+        if hash[char] == true
+          repeated = char+char
+        hash[repeated] = true
+        else 
+          hash[char] = true
+        end
+      else 
+        hash[char]= false
+      end
+    end
+    else 
+      return false
+  end
+
+  occurences = 0
+  hash.keys.each do |key|
+    if hash[key] == true
+      occurences +=1
+    end
+  end
+
+  if occurences == string1.length
+    return true
+  else 
+    return false
+  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