From 04f83e6daa9d89dc4be453270cc4dd81faefd680 Mon Sep 17 00:00:00 2001
From: gessica <gessicamohr18@gmail.com>
Date: Thu, 29 Apr 2021 14:27:40 -0700
Subject: [PATCH 1/2] implemented methods and tests are passing

---
 lib/heap_sort.rb      | 19 +++++++++++++++--
 lib/min_heap.rb       | 49 ++++++++++++++++++++++++++++++++++++++-----
 test/heapsort_test.rb |  2 +-
 3 files changed, 62 insertions(+), 8 deletions(-)

diff --git a/lib/heap_sort.rb b/lib/heap_sort.rb
index c8a32a4..f6793e4 100644
--- a/lib/heap_sort.rb
+++ b/lib/heap_sort.rb
@@ -3,6 +3,21 @@
 # This method uses a heap to sort an array.
 # Time Complexity:  ?
 # Space Complexity: ?
-def heap_sort(list)
-  raise NotImplementedError, "Method not implemented yet..."
+def heapsort(list)
+  # raise NotImplementedError, "Method not implemented yet..."
+
+  heap = MinHeap.new
+
+  list.each do |element|
+    heap.add(element)
+  end 
+
+  sorted_list = []
+
+  until heap.empty?
+    sorted_list.push(heap.remove)
+  end
+
+  return sorted_list
+
 end
\ No newline at end of file
diff --git a/lib/min_heap.rb b/lib/min_heap.rb
index 6eaa630..dfdba61 100644
--- a/lib/min_heap.rb
+++ b/lib/min_heap.rb
@@ -17,7 +17,10 @@ def initialize
   # Time Complexity: ?
   # Space Complexity: ?
   def add(key, value = key)
-    raise NotImplementedError, "Method not implemented yet..."
+    # raise NotImplementedError, "Method not implemented yet..."
+    @store << HeapNode.new(key, value)
+
+    heap_up(@store.length - 1)
   end
 
   # This method removes and returns an element from the heap
@@ -25,7 +28,17 @@ def add(key, value = key)
   # Time Complexity: ?
   # Space Complexity: ?
   def remove()
-    raise NotImplementedError, "Method not implemented yet..."
+    # raise NotImplementedError, "Method not implemented yet..."
+    if @store.empty?
+      return nil
+    end
+
+    swap(0, @store.length - 1)
+    result = @store.pop.value
+
+    heap_down(0) unless @store.empty?
+    return result
+
   end
 
 
@@ -47,7 +60,8 @@ def to_s
   # Time complexity: ?
   # Space complexity: ?
   def empty?
-    raise NotImplementedError, "Method not implemented yet..."
+    # raise NotImplementedError, "Method not implemented yet..."
+    return @store.empty?
   end
 
   private
@@ -58,14 +72,39 @@ def empty?
   # Time complexity: ?
   # Space complexity: ?
   def heap_up(index)
-    
+    return nil if index == 0
+
+    parent_index = (index - 1)/ 2
+
+    if @store[index].key < @store[parent_index].key
+      swap(index, parent_index)
+      heap_up(parent_index)
+    else
+      return nil
+    end
+
   end
 
   # This helper method takes an index and 
   #  moves it up the heap if it's smaller
   #  than it's parent node.
   def heap_down(index)
-    raise NotImplementedError, "Method not implemented yet..."
+    # raise NotImplementedError, "Method not implemented yet..."
+    left_child = (index * 2) + 1
+    right_child = (index * 2) + 2
+
+    return @store if @store[left_child].nil? || @store[right_child].nil?
+
+    if @store[left_child].key < @store[index].key
+      swap(left_child, index)
+      heap_down(left_child)
+    end
+
+    if @store[right_child].key < @store[index].key
+      swap(right_child, index)
+      heap_down(right_child)
+    end
+
   end
 
   # If you want a swap method... you're welcome
diff --git a/test/heapsort_test.rb b/test/heapsort_test.rb
index 34402ac..7ce79b7 100644
--- a/test/heapsort_test.rb
+++ b/test/heapsort_test.rb
@@ -1,6 +1,6 @@
 require_relative "test_helper"
 
-xdescribe "heapsort" do
+describe "heapsort" do
   it "sorts an empty array" do
     # Arrange 
     list = []

From 743383e55609370fba4a8c4c1c15cf91ede0dfae Mon Sep 17 00:00:00 2001
From: gessica <gessicamohr18@gmail.com>
Date: Thu, 29 Apr 2021 14:45:19 -0700
Subject: [PATCH 2/2] added time and space complexity to all methods

---
 lib/heap_sort.rb |  4 ++--
 lib/min_heap.rb  | 16 ++++++++--------
 2 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/lib/heap_sort.rb b/lib/heap_sort.rb
index f6793e4..73eb394 100644
--- a/lib/heap_sort.rb
+++ b/lib/heap_sort.rb
@@ -1,8 +1,8 @@
 
 
 # This method uses a heap to sort an array.
-# Time Complexity:  ?
-# Space Complexity: ?
+# Time Complexity:  O(nlog(n))
+# Space Complexity: O(n)
 def heapsort(list)
   # raise NotImplementedError, "Method not implemented yet..."
 
diff --git a/lib/min_heap.rb b/lib/min_heap.rb
index dfdba61..5ece5de 100644
--- a/lib/min_heap.rb
+++ b/lib/min_heap.rb
@@ -14,8 +14,8 @@ def initialize
   end
 
   # This method adds a HeapNode instance to the heap
-  # Time Complexity: ?
-  # Space Complexity: ?
+  # Time Complexity: O(log(n))
+  # Space Complexity: O(log(n))
   def add(key, value = key)
     # raise NotImplementedError, "Method not implemented yet..."
     @store << HeapNode.new(key, value)
@@ -25,8 +25,8 @@ def add(key, value = key)
 
   # This method removes and returns an element from the heap
   #   maintaining the heap structure
-  # Time Complexity: ?
-  # Space Complexity: ?
+  # Time Complexity: O(log(n))
+  # Space Complexity: O(log(n))
   def remove()
     # raise NotImplementedError, "Method not implemented yet..."
     if @store.empty?
@@ -57,8 +57,8 @@ def to_s
   end
 
   # This method returns true if the heap is empty
-  # Time complexity: ?
-  # Space complexity: ?
+  # Time complexity: O(1)
+  # Space complexity: O(1)
   def empty?
     # raise NotImplementedError, "Method not implemented yet..."
     return @store.empty?
@@ -69,8 +69,8 @@ def empty?
   # This helper method takes an index and
   #  moves it up the heap, if it is less than it's parent node.
   #  It could be **very** helpful for the add method.
-  # Time complexity: ?
-  # Space complexity: ?
+  # Time complexity: O(log(n))
+  # Space complexity: O(log(n))
   def heap_up(index)
     return nil if index == 0