def should_rotate_left():
'''
4 4
| => |
------- -------
/ \ / \
2 6 3 6
| | / |
----- ----- 2 -----
/ \ / \ / / \
1 3 5 7 1 5 7
'''
tree = sample_tree()
before_inorder = inorder(tree)
rotate_left(tree.left)
assert before_inorder == inorder(tree)
assert 3 == tree.left.value
assert 2 == tree.left.left.value
assert 1 == tree.left.left.left.value
rotate_right(tree.left)
assert sample_tree().equivalent(tree)
def should_rotate_left():
'''
4 4
| => |
------- -------
/ \ / \
2 6 3 6
| | / |
----- ----- 2 -----
/ \ / \ / / \
1 3 5 7 1 5 7
'''
tree = sample_tree()
before_inorder = inorder(tree)
rotate_left(tree.left)
assert before_inorder == inorder(tree)
assert 3 == tree.left.value
assert 2 == tree.left.left.value
assert 1 == tree.left.left.left.value
rotate_right(tree.left)
assert sample_tree().equivalent(tree)
def should_rotate_right():
'''
4 2
| => |
------- -------
/ \ / \
2 6 1 4
| | / \
----- ----- 3 6
/ \ / \ |
1 3 5 7 -----
/ \
5 7
'''
four = sample_tree()
rotate_right(four)
assert [3, 4, 5, 6, 7] == inorder(four)
assert 3 == four.left.value
assert four.equivalent(four.left.parent)
two = four.parent
assert 2 == two.value
assert not two.parent # 2 is root
original_tree = sample_tree()
assert inorder(original_tree) == inorder(two)
rotate_left(two)
assert four.equivalent(original_tree)
assert not four.parent # 4 is root again
assert 2 == four.left.value
assert 6 == four.right.value
three = four.left.right
assert 3 == three.value
assert 2 == three.parent.value
assert 4 == three.parent.parent.value
def should_rotate_right():
'''
4 2
| => |
------- -------
/ \ / \
2 6 1 4
| | / \
----- ----- 3 6
/ \ / \ |
1 3 5 7 -----
/ \
5 7
'''
four = sample_tree()
rotate_right(four)
assert [3, 4, 5, 6, 7] == inorder(four)
assert 3 == four.left.value
assert four.equivalent(four.left.parent)
two = four.parent
assert 2 == two.value
assert not two.parent # 2 is root
original_tree = sample_tree()
assert inorder(original_tree) == inorder(two)
rotate_left(two)
assert four.equivalent(original_tree)
assert not four.parent # 4 is root again
assert 2 == four.left.value
assert 6 == four.right.value
three = four.left.right
assert 3 == three.value
assert 2 == three.parent.value
assert 4 == three.parent.parent.value