Time - Yaz

lib/array_intersection.rb

@@ -1,3 +1,23 @@
 def intersection(list1, list2)
-  raise NotImplementedError, "Intersection not implemented"
+  intersection = {}
+  short_list = []
+  long_list = []
+  results = []
+  if list1.length < list2.length 
+    short_list = list1
+    long_list = list2
+  else
+    short_list = list2
+    long_list = list1
+  end
+  short_list.each do |num|
+    intersection[num] = true
+  end
+
+  long_list.each do |num|
+    if intersection[num]
+      results.push(num)
+    end
+  end
+  return results
 end

lib/palindrome_permutation.rb

@@ -1,4 +1,23 @@
 
 def palindrome_permutation?(string)
-  raise NotImplementedError, "palindrome_permutation? not implemented"
-end
+  array_string = string.chars
+  palindrome_chars = Hash.new(0) 
+  array_string.each do |ch|
+    palindrome_chars[ch] += 1
+  end
+  char_counts = palindrome_chars.values
+  puts char_counts
+  if string.length % 2 != 0
+    middle_char = char_counts.find_index {|i|
+      i % 2 == 1
+    }
+    if middle_char == nil
+      return false
+    end
+    char_counts.delete_at(middle_char)
+  end
+  return char_counts.all? { |ch_num|
+    ch_num % 2 == 0 || ch_num == 0
+  }
+end
+palindrome_permutation?('carrace')

lib/permutations.rb

@@ -1,4 +1,18 @@
 
 def permutations?(string1, string2)
-  raise NotImplementedError, "permutations? not implemented"
+  if string1.length != string2.length
+    return false
+  end
+  common_chars = Hash.new(0)
+  string1.chars.each do |ch|
+    common_chars[ch] += 1
+  end
+  string2.chars.each do |ch|
+    if common_chars[ch] == 0
+      return false
+    else
+      common_chars[ch] -= 1
+    end
+  end
+  return true
 end

test/array_intersection_test.rb

@@ -1,5 +1,6 @@
 require_relative "test_helper"
 
+
 describe "Array Intersection" do
   it "returns [4] for [2, 3, 4], and [4, 5, 6]" do
     expect(intersection([2, 3, 4], [4, 5, 6])).must_equal [4]

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
@@ -9,7 +9,7 @@
     expect(permutations?("hello", "ehllo")).must_equal true
   end
 
-  it "returns true for 'heelo', 'ehllo'" do
+  it "returns false for 'heelo', 'ehllo'" do
     expect(permutations?("heelo", "ehllo")).must_equal false
   end
   it "returns true for 'pasta', 'atsap'" do