From 60c73200f46c027930b868f1bf6ffaa524ed7e85 Mon Sep 17 00:00:00 2001
From: Yieni <yaynee8d@gmail.com>
Date: Thu, 2 Apr 2020 00:51:28 -0700
Subject: [PATCH 1/5] final code

---
 lib/array_intersection.rb           | 30 ++++++++++++++++++++++++++-
 lib/palindrome_permutation.rb       | 25 +++++++++++++++++++++-
 lib/permutations.rb                 | 32 ++++++++++++++++++++++++++++-
 test/palindrome_permutation_test.rb |  2 +-
 test/permutations_test.rb           |  2 +-
 5 files changed, 86 insertions(+), 5 deletions(-)

diff --git a/lib/array_intersection.rb b/lib/array_intersection.rb
index ac8771f..e6891ab 100644
--- a/lib/array_intersection.rb
+++ b/lib/array_intersection.rb
@@ -1,3 +1,31 @@
 def intersection(list1, list2)
-  raise NotImplementedError, "Intersection not implemented"
+  hash_table = {}
+  intersection_array = []
+  if list1.length < list2.length
+    list1.each do |num|
+      hash_table[num] = true
+    end
+
+    list2.each do |num|
+      intersection_array << num if hash_table[num] != nil
+    end
+  elsif list2.length < list1.length
+    list2.each do |num|
+      hash_table[num] = false
+    end
+
+    list1.each do |num|
+      intersection_array << num if hash_table[num] != nil
+    end
+  else 
+    list1.each do |num|
+      hash_table[num] = false
+    end
+    
+    list2.each do |num|
+      intersection_array << num if hash_table[num] != nil
+    end
+  end
+  
+  return intersection_array
 end
\ No newline at end of file
diff --git a/lib/palindrome_permutation.rb b/lib/palindrome_permutation.rb
index f113692..8a2dc60 100644
--- a/lib/palindrome_permutation.rb
+++ b/lib/palindrome_permutation.rb
@@ -1,4 +1,27 @@
 
 def palindrome_permutation?(string)
-  raise NotImplementedError, "palindrome_permutation? not implemented"
+  return true if string.length == 1 || string.length == 0
+
+  split_string = string.chars
+  hash_table = {}
+
+  split_string.each do |char|
+    value = hash_table[char]
+    hash_table[char]? hash_table[char] = value +1 : hash_table[char] = 1
+  end
+
+  if string.length.even? 
+    odd_count = 0
+    hash_table.values.each do |value|
+      odd_count += 1 if value.odd?
+    end
+    odd_count == 0?  true :  false
+
+  elsif string.length.odd? 
+    odd_count = 0
+    hash_table.values.each do |value|
+      odd_count += 1 if value.odd?
+    end
+    return odd_count == 1
+  end
 end
\ No newline at end of file
diff --git a/lib/permutations.rb b/lib/permutations.rb
index 3b08381..b821217 100644
--- a/lib/permutations.rb
+++ b/lib/permutations.rb
@@ -1,4 +1,34 @@
 
 def permutations?(string1, string2)
-  raise NotImplementedError, "permutations? not implemented"
+  return true if string1.empty? && string2.empty?
+  
+  split_string1 = string1.chars
+  split_string2 = string2.chars
+
+  hash_table = {}
+  
+  split_string1.each do |char|
+    if hash_table[char] == nil
+      hash_table[char] = 1
+    else
+      value = hash_table[char]
+      hash_table[char] = value + 1
+    end
+  end
+
+  split_string2.each do |char|
+    value = hash_table[char]
+    if hash_table[char] == nil 
+      return false
+    else
+      hash_table[char] = value - 1
+    end
+  end
+
+  if hash_table.values.min < 0 || hash_table.values.max > 0
+    return false
+  elsif hash_table.values.sum == 0
+    return true
+  end
+
 end
\ No newline at end of file
diff --git a/test/palindrome_permutation_test.rb b/test/palindrome_permutation_test.rb
index 6e43777..246ccfd 100644
--- a/test/palindrome_permutation_test.rb
+++ b/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
diff --git a/test/permutations_test.rb b/test/permutations_test.rb
index eb1ce8c..792d9ef 100644
--- a/test/permutations_test.rb
+++ b/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

From 7b3640099218fbc151b288fd1188640be8961efc Mon Sep 17 00:00:00 2001
From: Yieni <yaynee8d@gmail.com>
Date: Thu, 2 Apr 2020 02:03:44 -0700
Subject: [PATCH 2/5] refactor permutation

---
 lib/permutations.rb | 14 +++-----------
 1 file changed, 3 insertions(+), 11 deletions(-)

diff --git a/lib/permutations.rb b/lib/permutations.rb
index b821217..cee0030 100644
--- a/lib/permutations.rb
+++ b/lib/permutations.rb
@@ -8,21 +8,13 @@ def permutations?(string1, string2)
   hash_table = {}
   
   split_string1.each do |char|
-    if hash_table[char] == nil
-      hash_table[char] = 1
-    else
-      value = hash_table[char]
-      hash_table[char] = value + 1
-    end
+    value = hash_table[char]
+    hash_table[char] ? hash_table[char] = value + 1 : hash_table[char] = 1
   end
 
   split_string2.each do |char|
     value = hash_table[char]
-    if hash_table[char] == nil 
-      return false
-    else
-      hash_table[char] = value - 1
-    end
+    hash_table[char] ? hash_table[char] = value - 1 :  false
   end
 
   if hash_table.values.min < 0 || hash_table.values.max > 0

From 6da396420fd5dc64ecae5cf913ff0b956a79701b Mon Sep 17 00:00:00 2001
From: Yieni <yaynee8d@gmail.com>
Date: Thu, 2 Apr 2020 02:13:50 -0700
Subject: [PATCH 3/5]  refactor array intersectiom

---
 lib/array_intersection.rb | 31 +++++++------------------------
 1 file changed, 7 insertions(+), 24 deletions(-)

diff --git a/lib/array_intersection.rb b/lib/array_intersection.rb
index e6891ab..d646c03 100644
--- a/lib/array_intersection.rb
+++ b/lib/array_intersection.rb
@@ -1,31 +1,14 @@
 def intersection(list1, list2)
   hash_table = {}
   intersection_array = []
-  if list1.length < list2.length
-    list1.each do |num|
-      hash_table[num] = true
-    end
-
-    list2.each do |num|
-      intersection_array << num if hash_table[num] != nil
-    end
-  elsif list2.length < list1.length
-    list2.each do |num|
-      hash_table[num] = false
-    end
-
-    list1.each do |num|
-      intersection_array << num if hash_table[num] != nil
-    end
-  else 
-    list1.each do |num|
-      hash_table[num] = false
-    end
-    
-    list2.each do |num|
-      intersection_array << num if hash_table[num] != nil
-    end
+ 
+  list1.each do |num|
+    hash_table[num] = 1
   end
   
+  list2.each do |num|
+    intersection_array << num if hash_table[num]
+  end
+
   return intersection_array
 end
\ No newline at end of file

From 41aa100ca710b2075bd544dfa4d0e5d324219d86 Mon Sep 17 00:00:00 2001
From: Yieni <yaynee8d@gmail.com>
Date: Thu, 2 Apr 2020 02:17:35 -0700
Subject: [PATCH 4/5] add space and time complexity

---
 lib/array_intersection.rb     | 3 +++
 lib/palindrome_permutation.rb | 3 ++-
 lib/permutations.rb           | 2 ++
 3 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/lib/array_intersection.rb b/lib/array_intersection.rb
index d646c03..1e0ad4d 100644
--- a/lib/array_intersection.rb
+++ b/lib/array_intersection.rb
@@ -1,3 +1,6 @@
+# time complexity: O(n + m)
+# space complexity: O(n)
+
 def intersection(list1, list2)
   hash_table = {}
   intersection_array = []
diff --git a/lib/palindrome_permutation.rb b/lib/palindrome_permutation.rb
index 8a2dc60..04734b5 100644
--- a/lib/palindrome_permutation.rb
+++ b/lib/palindrome_permutation.rb
@@ -1,4 +1,5 @@
-
+# time complexity: O(n)
+# space complexity: O(n)
 def palindrome_permutation?(string)
   return true if string.length == 1 || string.length == 0
 
diff --git a/lib/permutations.rb b/lib/permutations.rb
index cee0030..d155f7b 100644
--- a/lib/permutations.rb
+++ b/lib/permutations.rb
@@ -1,3 +1,5 @@
+# time complexity: O(n + m)
+# space complexity: O(n)
 
 def permutations?(string1, string2)
   return true if string1.empty? && string2.empty?

From 7e77ad6f8090d617b52756dc50db87d1d98d25cc Mon Sep 17 00:00:00 2001
From: Yieni <yaynee8d@gmail.com>
Date: Thu, 2 Apr 2020 02:34:04 -0700
Subject: [PATCH 5/5] drying up palindrome and cleaining up permutations

---
 lib/palindrome_permutation.rb | 17 ++++-------------
 lib/permutations.rb           |  6 +-----
 2 files changed, 5 insertions(+), 18 deletions(-)

diff --git a/lib/palindrome_permutation.rb b/lib/palindrome_permutation.rb
index 04734b5..a384873 100644
--- a/lib/palindrome_permutation.rb
+++ b/lib/palindrome_permutation.rb
@@ -11,18 +11,9 @@ def palindrome_permutation?(string)
     hash_table[char]? hash_table[char] = value +1 : hash_table[char] = 1
   end
 
-  if string.length.even? 
-    odd_count = 0
-    hash_table.values.each do |value|
-      odd_count += 1 if value.odd?
-    end
-    odd_count == 0?  true :  false
-
-  elsif string.length.odd? 
-    odd_count = 0
-    hash_table.values.each do |value|
-      odd_count += 1 if value.odd?
-    end
-    return odd_count == 1
+  odd_count = 0
+  hash_table.values.each do |value|
+    odd_count += 1 if value.odd?
   end
+  odd_count <= 1 ?  true :  false
 end
\ No newline at end of file
diff --git a/lib/permutations.rb b/lib/permutations.rb
index d155f7b..5dd0902 100644
--- a/lib/permutations.rb
+++ b/lib/permutations.rb
@@ -19,10 +19,6 @@ def permutations?(string1, string2)
     hash_table[char] ? hash_table[char] = value - 1 :  false
   end
 
-  if hash_table.values.min < 0 || hash_table.values.max > 0
-    return false
-  elsif hash_table.values.sum == 0
-    return true
-  end
+  return hash_table.values.sum == 0 && hash_table.values.min == 0 ? true : false
 
 end
\ No newline at end of file