diff --git a/lib/heap_sort.rb b/lib/heap_sort.rb
index 6b692e4..e762cb4 100644
--- a/lib/heap_sort.rb
+++ b/lib/heap_sort.rb
@@ -1,8 +1,25 @@
-
+require_relative 'min_heap'
+require 'pry'
 
 # This method uses a heap to sort an array.
-# Time Complexity:  ?
-# Space Complexity: ?
+# Time Complexity:  O(n log n)
+# Space Complexity: O(n)
 def heapsort(list)
-  raise NotImplementedError, "Method not implemented yet..."
+
+  return [] if list.empty?
+  # create heap
+  heap = MinHeap.new
+  
+  list.each do |element|
+    heap.add(element)
+  end
+
+  until heap.empty?
+    current = heap.remove
+    list.push(current)
+    list.shift unless list.length == 1
+  end
+
+  return list
+
 end
\ No newline at end of file
diff --git a/lib/min_heap.rb b/lib/min_heap.rb
index 6eaa630..e2f51e2 100644
--- a/lib/min_heap.rb
+++ b/lib/min_heap.rb
@@ -1,3 +1,4 @@
+
 class HeapNode
   attr_reader :key, :value
 
@@ -14,18 +15,28 @@ def initialize
   end
 
   # This method adds a HeapNode instance to the heap
-  # Time Complexity: ?
-  # Space Complexity: ?
+  # Time Complexity: O(n)
+  # Space Complexity: O(1)
   def add(key, value = key)
-    raise NotImplementedError, "Method not implemented yet..."
+    
+    @store.push(HeapNode.new(key,value))
+    child = @store.length - 1
+    heap_up(child) if child != 0 
+
   end
 
   # This method removes and returns an element from the heap
   #   maintaining the heap structure
-  # Time Complexity: ?
-  # Space Complexity: ?
+  # Time Complexity: O(n)
+  # Space Complexity: O(1)
   def remove()
-    raise NotImplementedError, "Method not implemented yet..."
+
+    swap(0, @store.length - 1)
+    deleted = @store.pop
+    heap_down(0) unless self.empty?
+
+    return deleted.value
+
   end
 
 
@@ -44,10 +55,15 @@ 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..."
+    if @store[0].nil? || @store.empty?
+      return true
+    end
+
+    return false
+
   end
 
   private
@@ -55,17 +71,45 @@ 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(n)
+  # Space complexity: O(1)
   def heap_up(index)
-    
+
+    parent = (index - 2) / 2 if index.even?
+    parent = (index - 1) / 2 if index.odd?
+
+    if @store[parent].key > @store[index].key
+      swap(parent, index)
+      heap_up(parent) if parent != 0
+    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..."
+  
+    left = (2 * index) + 1
+    right = (2 * index) + 2
+
+
+    if !@store[right].nil?
+      min_child = left if @store[left].key < @store[right].key
+      min_child = right if @store[left].key > @store[right].key
+    elsif @store[left].nil?
+      return
+    else
+      min_child = left
+    end
+
+    if @store[index].key > @store[min_child].key
+      swap(index, min_child)
+      index = min_child
+      heap_down(index)
+    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 = []
diff --git a/test/min_heap_test.rb b/test/min_heap_test.rb
index 186d4c2..d3193fc 100644
--- a/test/min_heap_test.rb
+++ b/test/min_heap_test.rb
@@ -59,6 +59,7 @@
    heap.add(0, "Donuts")
    heap.add(16, "Cookies")
    heap.add(57, "Cake")
+   
 
    # Act
    removed = heap.remove