def test_sift_up(self):
"""
Sifting up an element swaps it with its parent when appropriate, and
continues to sift up that element from its new position, until it either
becomes the root or its parent's value is larger than its value.
"""
h = MaxHeap()
h._data.append(600)
h._data.append(500)
h._data.append(8)
h._data.append(7)
h._data.append(6)
h._data.append(5)
h._data.append(4)
h._data.append(3)
h._data.append(2)
h._data.append(1)
h._data.append(42)
h._sift_up(10)
self.assertEqual(600, h._data[0])
self.assertEqual(500, h._data[1])
self.assertEqual(8, h._data[2])
self.assertEqual(7, h._data[3])
self.assertEqual(42, h._data[4])
self.assertEqual(5, h._data[5])
self.assertEqual(4, h._data[6])
self.assertEqual(3, h._data[7])
self.assertEqual(2, h._data[8])
self.assertEqual(1, h._data[9])
self.assertEqual(6, h._data[10])
def test_sift_up_one(self):
"""
Sifting up the root is easy.
Hint: Be naive for now.
"""
h = MaxHeap()
h._data.append(1)
h._sift_up(0)
self.assertEqual(1, h._data[0])
def test_sift_up_two_unstable(self):
"""
Sifting up an element in a two-element heap, when the element is larger
than its parent swaps the element with its parent.
Hint: A little more genuine now. Refine your logic. Use your abstractions.
"""
h = MaxHeap()
h._data.append(1)
h._data.append(5)
# Sifting up the leaf of this tree swaps it with its parent.
h._sift_up(1)
self.assertEqual(5, h._data[0])
self.assertEqual(1, h._data[1])
def test_sift_up_three_unstable_left(self):
"""
Sifting up an element in a three-element heap, when the element is
larger than its parent, swaps it with its parent.
"""
h = MaxHeap()
h._data.append(1)
h._data.append(10)
h._data.append(5)
# Sifting up the left leaf of this tree swaps it with its parent.
h._sift_up(1)
self.assertEqual(10, h._data[0])
self.assertEqual(1, h._data[1])
self.assertEqual(5, h._data[2])
def test_sift_up_three_unstable_right(self):
"""
Sifting up an element in a three-element heap, when the leaf is
greater than its parent, swaps it with its parent.
Hint: Refine your logic.
"""
h = MaxHeap()
h._data.append(1)
h._data.append(5)
h._data.append(10)
# Sifting up the right leaf of this tree swaps it with its parent.
h._sift_up(2)
self.assertEqual(10, h._data[0])
self.assertEqual(5, h._data[1])
self.assertEqual(1, h._data[2])
def test_sift_up_two_stable(self):
"""
Sifting up an element in a two-element heap, when the element is smaller
than its parent, is easy.
Hint: Be naive for now.
"""
h = MaxHeap()
h._data.append(5)
h._data.append(1)
# Sifting up the root of this tree doesn't change anything.
h._sift_up(0)
self.assertEqual(5, h._data[0])
self.assertEqual(1, h._data[1])
# Sifting up the last element of this tree doesn't change anything, either.
h._sift_up(1)
self.assertEqual(5, h._data[0])
self.assertEqual(1, h._data[1])
