From 1ed8fc6e70f7385c0c5b2e0c6c111c03ebc320d4 Mon Sep 17 00:00:00 2001
From: Ida <ida.goitom@yahoo.com>
Date: Tue, 27 Jul 2021 16:37:57 -0700
Subject: [PATCH] all tests passing

---
 lib/heap_sort.rb      | 19 ++++++++++---
 lib/min_heap.rb       | 66 ++++++++++++++++++++++++++++++++++---------
 test/heapsort_test.rb |  8 +++---
 3 files changed, 72 insertions(+), 21 deletions(-)

diff --git a/lib/heap_sort.rb b/lib/heap_sort.rb
index c8a32a4..64cc9b2 100644
--- a/lib/heap_sort.rb
+++ b/lib/heap_sort.rb
@@ -1,8 +1,19 @@
-
+require_relative "./min_heap"
 
 # This method uses a heap to sort an array.
-# Time Complexity:  ?
-# Space Complexity: ?
+# Time Complexity:  o(log n)
+# Space Complexity: o(n)
 def heap_sort(list)
-  raise NotImplementedError, "Method not implemented yet..."
+    heap = MinHeap.new
+
+    list.each do |item|
+        heap.add(item)
+    end
+
+    sorted_list = []
+    until heap.empty?
+        sorted_list << 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..0b0a54e 100644
--- a/lib/min_heap.rb
+++ b/lib/min_heap.rb
@@ -14,18 +14,29 @@ def initialize
   end
 
   # This method adds a HeapNode instance to the heap
-  # Time Complexity: ?
-  # Space Complexity: ?
+  # Time Complexity: o(log n)
+  # Space Complexity: o(n)
   def add(key, value = key)
-    raise NotImplementedError, "Method not implemented yet..."
+
+  new_node = HeapNode.new(key, value)
+  @store.push(new_node)
+
+  heap_up(@store.length - 1)
+
   end
 
   # 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..."
+
+    return if @store.empty?
+  
+    swap(0, @store.length - 1)
+    removed_result = @store.pop
+    heap_down(0) unless @store.empty?
+    return removed_result.value
   end
 
 
@@ -44,10 +55,10 @@ 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?
   end
 
   private
@@ -55,17 +66,46 @@ 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 if index == 0
+
+    parent = (index - 1) / 2
+    if @store[parent].key > @store[index].key
+      swap(parent, index)
+      heap_up(parent)
+    else
+      return
+    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_index = index * 2 + 1
+      right_index = index * 2 + 2
+      return if left_index >= @store.length
+      child = nil
+      left = @store[left_index]
+      right = @store[right_index]
+      if left && right
+        child = left.key < right.key ? left_index : right_index
+        if @store[child].key < @store[index].key
+          swap(index, child)
+          index = child
+        else
+          return
+        end
+      elsif left && !right
+        return unless left.key < @store[index].key
+        child = left_index
+        swap(index, child)
+        index = child
+      else
+        return
+      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..271e711 100644
--- a/test/heapsort_test.rb
+++ b/test/heapsort_test.rb
@@ -1,12 +1,12 @@
 require_relative "test_helper"
 
-xdescribe "heapsort" do
+describe "heapsort" do
   it "sorts an empty array" do
     # Arrange 
     list = []
 
     # Act
-    result = heapsort(list)
+    result = heap_sort(list)
 
     # Assert
     expect(result).must_equal []
@@ -17,7 +17,7 @@
     list = [5]
 
     # Act
-    result = heapsort(list)
+    result = heap_sort(list)
 
     # Assert
     expect(result).must_equal [5]
@@ -28,7 +28,7 @@
     list = [5, 27, 3, 16, -50]
 
     # Act
-    result = heapsort(list)
+    result = heap_sort(list)
 
     # Assert
     expect(result).must_equal [-50, 3, 5, 16, 27]