def delete_single_child_node():
"""
5 5B
/ \ should become /
1R 6R 1R
"""
rb_tree = RBTree()
root = Node(value=5, color=BLACK, parent=None, left=NIL_LEAF, right=NIL_LEAF)
left_child = Node(value=1, color=RED, parent=root, left=NIL_LEAF, right=NIL_LEAF)
right_child = Node(value=6, color=RED, parent=root, left=NIL_LEAF, right=NIL_LEAF)
root.left = left_child
root.right = right_child
rb_tree.root = root
rb_tree.remove(6)
return list(rb_tree) == [1, 5]
def delete_root_two_nodes():
"""
__5B__ <-- REMOVE __8B__
\ Should become--^
8R
"""
rb_tree = RBTree()
root = Node(value=5, color=BLACK, parent=None, left=NIL_LEAF, right=NIL_LEAF)
right_child = Node(value=8, color=RED, parent=root, left=NIL_LEAF, right=NIL_LEAF)
root.right = right_child
rb_tree.root = root
rb_tree.remove(5)
return list(rb_tree) == [8]
def delete_root():
"""
REMOVE--> __5__ __8B__
/ \ --Result--> /
3R 8R 3R
"""
rb_tree = RBTree()
root = Node(value=5, color=BLACK, parent=None, left=NIL_LEAF, right=NIL_LEAF)
left_child = Node(value=3, color=RED, parent=root, left=NIL_LEAF, right=NIL_LEAF)
right_child = Node(value=8, color=RED, parent=root, left=NIL_LEAF, right=NIL_LEAF)
root.left = left_child
root.right = right_child
rb_tree.root = root
rb_tree.remove(5)
return list(rb_tree) == [3, 8]
def delete_single_deep_child():
"""
______20______
/ \
10B ___38R___
/ \ / \
5R 15R 28B 48B
/ \ / \
23R 29R 41R 49R <--- REMOVE
"""
rb_tree = RBTree()
root = Node(value=20, color=BLACK, parent=None, left=NIL_LEAF, right=NIL_LEAF)
# left subtree
node_10 = Node(value=10, color=BLACK, parent=None, left=NIL_LEAF, right=NIL_LEAF)
node_5 = Node(value=5, color=RED, parent=node_10, left=NIL_LEAF, right=NIL_LEAF)
node_15 = Node(value=15, color=RED, parent=node_10, left=NIL_LEAF, right=NIL_LEAF)
node_10.left = node_5
node_10.right = node_15
# right subtree
node_38 = Node(value=38, color=RED, parent=root, left=NIL_LEAF, right=NIL_LEAF)
node_28 = Node(value=28, color=BLACK, parent=node_38, left=NIL_LEAF, right=NIL_LEAF)
node_48 = Node(value=48, color=BLACK, parent=node_38, left=NIL_LEAF, right=NIL_LEAF)
node_38.left = node_28
node_38.right = node_48
# node_28 subtree
node_23 = Node(value=23, color=RED, parent=node_28, left=NIL_LEAF, right=NIL_LEAF)
node_29 = Node(value=29, color=RED, parent=node_28, left=NIL_LEAF, right=NIL_LEAF)
node_28.left = node_23
node_28.right = node_29
# node 48 subtree
node_41 = Node(value=41, color=RED, parent=node_48, left=NIL_LEAF, right=NIL_LEAF)
node_49 = Node(value=49, color=RED, parent=node_48, left=NIL_LEAF, right=NIL_LEAF)
node_48.left = node_41
node_48.right = node_49
root.left = node_10
root.right = node_38
rb_tree.root = root
rb_tree.remove(49)
return list(rb_tree) == [5, 10, 15, 20, 23, 28, 29, 38, 41, 48]
def delete_black_node_black_successor_red_child():
"""
___10B___ ___10B___
/ \ / \
5B 30B <------- REMOVE THIS 5B 32B <----
/ \ / \ / \ / \
-5B 7B 20B 38R -5B 7B 20B 38R
/ \ / \
successor ---> 32B 41B --> 35B 41B
\ 30B becomes 32B
35R old 32B becomes 35B
"""
rb_tree = RBTree()
root = Node(value=10, color=BLACK, parent=None, left=NIL_LEAF, right=NIL_LEAF)
# left subtree
node_5 = Node(value=5, color=BLACK, parent=root, left=NIL_LEAF, right=NIL_LEAF)
node_m5 = Node(value=-5, color=BLACK, parent=node_5, left=NIL_LEAF, right=NIL_LEAF)
node_7 = Node(value=7, color=BLACK, parent=node_5, left=NIL_LEAF, right=NIL_LEAF)
node_5.left = node_m5
node_5.right = node_7
# right subtree
node_30 = Node(value=30, color=BLACK, parent=root, left=NIL_LEAF, right=NIL_LEAF)
node_20 = Node(value=20, color=BLACK, parent=node_30, left=NIL_LEAF, right=NIL_LEAF)
node_38 = Node(value=38, color=RED, parent=node_30, left=NIL_LEAF, right=NIL_LEAF)
node_30.left = node_20
node_30.right = node_38
# 38 subtree
node_32 = Node(value=32, color=BLACK, parent=node_38, left=NIL_LEAF, right=NIL_LEAF)
node_41 = Node(value=41, color=BLACK, parent=node_38, left=NIL_LEAF, right=NIL_LEAF)
node_38.left = node_32
node_38.right = node_41
node_35 = Node(value=35, color=RED, parent=node_32, left=NIL_LEAF, right=NIL_LEAF)
node_32.right = node_35
root.left = node_5
root.right = node_30
rb_tree.root = root
rb_tree.remove(30)
return list(rb_tree) == [-5, 5, 7, 10, 20, 32, 35, 38, 41]