def should_delete_double_black():
'''
delete 3
2 2
/ \ => /
1 3 (1)
8
|
---------
/ \
4 12
| |
---- ----
/ \ / \
2 6 10 14
/ \ / \ / \ / \
1 3 5 7 9 11 13 15
'''
tree1 = N(2, N(1), N(3))
tree1 = delete(3, tree1)
assert is_valid(tree1)
assert [1, 2] == inorder(tree1)
tree2 = N(8, N(4, N(2, N(1), N(3)), N(6, N(5), N(7))),
N(12, N(10, N(9), N(11)), N(14, N(13), N(15))))
for i in range(1, 16):
print strify(tree2)
assert is_valid(tree2)
assert range(i, 16) == inorder(tree2)
print "remove %s from %s" % (i, strify(tree2))
tree2 = delete(i, tree2)
assert not tree2
def should_delete_double_black():
'''
delete 3
2 2
/ \ => /
1 3 (1)
8
|
---------
/ \
4 12
| |
---- ----
/ \ / \
2 6 10 14
/ \ / \ / \ / \
1 3 5 7 9 11 13 15
'''
tree1 = N(2, N(1), N(3))
tree1 = delete(3, tree1)
assert is_valid(tree1)
assert [1, 2] == inorder(tree1)
tree2 =N(8,
N(4,
N(2, N(1), N(3)),
N(6, N(5), N(7))),
N(12,
N(10, N(9), N(11)),
N(14, N(13), N(15))))
for i in range(1, 16):
print strify(tree2)
assert is_valid(tree2)
assert range(i, 16) == inorder(tree2)
print "remove %s from %s" % (i, strify(tree2))
tree2 = delete(i, tree2)
assert not tree2
def should_delete_corner_cases():
'''
delete 4 in this tree
Example 1:
3 3
/ \ / \
2 (5) => 2 (7)
/ / \ / / \
(1) 4 7 (1) 5 8
/ \ X \
(6) (8) (4) (6)
Example 2:
sibling black with single red child.
Rotate to romve zig zag (if any) and rotate left.
3 3 3
/ \ / \ / \
2 (5) rotate right 2 (5) left 2 (6)
/ / \ => / / \ => / / \
(1) 4 7 (1) 4 6 (1) 5 7
/ \ X
(6) (7) (4)
Ex 3:
black node, black parent but one of sibling or sibling's children is red
3
|
3 -------
/ \ / \
1 5 1 7
/ \ / \ => / \ / \
1 2 4 (7) 1 2 5 8
/ \ X \
6 8 (4) (6)
3 3
| |
3 ------- -------
/ \ / \ => / \
1 5 1 5 1 6
/ \ / \ => / \ / \ / \ / \
1 2 4 7 1 2 4 6 1 2 5 7
/ \ X
(6) (7) (4)
'''
for tree in [
make_node(3, color=B,
left=make_node(2, color=B, left=make_node(1)),
right = make_node(5,
left=make_node(4, color=B),
right = make_node(7, color=B,
left=make_node(6),
right = make_node(8)))),
make_node(3, color=B,
left=make_node(1, color=B, left=make_node(1)),
right = make_node(5,
left=make_node(4, color=B),
right = make_node(7, color=B, left=make_node(6)))),
make_node(3, color=B,
left=make_node(1, color=B,
left=make_node(1, color=B),
right = make_node(2, color =B)),
right = make_node(5, color=B,
left=make_node(4, color=B),
right = make_node(7, color=B,
left=make_node(6),
right = make_node(8)))),
make_node(3, color=B,
left=make_node(1, color=B,
left=make_node(1, color=B),
right = make_node(2, color =B)),
right = make_node(5, color=B,
left=make_node(4, color=B),
right = make_node(7, color=B,
left=make_node(6))))]:
tree = assign_parents(tree)
assert is_valid(tree) # ensure test data is valid
vals = inorder(tree)
print strify(tree)
tree = delete(4, tree)
print strify(tree)
assert is_valid(tree)
vals.remove(4)
assert vals == inorder(tree)
def should_delete_corner_cases():
'''
delete 4 in this tree
Example 1:
3 3
/ \ / \
2 (5) => 2 (7)
/ / \ / / \
(1) 4 7 (1) 5 8
/ \ X \
(6) (8) (4) (6)
Example 2:
sibling black with single red child.
Rotate to romve zig zag (if any) and rotate left.
3 3 3
/ \ / \ / \
2 (5) rotate right 2 (5) left 2 (6)
/ / \ => / / \ => / / \
(1) 4 7 (1) 4 6 (1) 5 7
/ \ X
(6) (7) (4)
Ex 3:
black node, black parent but one of sibling or sibling's children is red
3
|
3 -------
/ \ / \
1 5 1 7
/ \ / \ => / \ / \
1 2 4 (7) 1 2 5 8
/ \ X \
6 8 (4) (6)
3 3
| |
3 ------- -------
/ \ / \ => / \
1 5 1 5 1 6
/ \ / \ => / \ / \ / \ / \
1 2 4 7 1 2 4 6 1 2 5 7
/ \ X
(6) (7) (4)
'''
for tree in [
make_node(3,
color=B,
left=make_node(2, color=B, left=make_node(1)),
right=make_node(5,
left=make_node(4, color=B),
right=make_node(7,
color=B,
left=make_node(6),
right=make_node(8)))),
make_node(3,
color=B,
left=make_node(1, color=B, left=make_node(1)),
right=make_node(5,
left=make_node(4, color=B),
right=make_node(7,
color=B,
left=make_node(6)))),
make_node(3,
color=B,
left=make_node(1,
color=B,
left=make_node(1, color=B),
right=make_node(2, color=B)),
right=make_node(5,
color=B,
left=make_node(4, color=B),
right=make_node(7,
color=B,
left=make_node(6),
right=make_node(8)))),
make_node(3,
color=B,
left=make_node(1,
color=B,
left=make_node(1, color=B),
right=make_node(2, color=B)),
right=make_node(5,
color=B,
left=make_node(4, color=B),
right=make_node(7,
color=B,
left=make_node(6))))
]:
tree = assign_parents(tree)
assert is_valid(tree) # ensure test data is valid
vals = inorder(tree)
print strify(tree)
tree = delete(4, tree)
print strify(tree)
assert is_valid(tree)
vals.remove(4)
assert vals == inorder(tree)
