def test_successor_returns_successor_given_right_subtree_exists():
bst = BinarySearchTree(5)
bst.insert_node(TreeNode(8))
bst.insert_node(TreeNode(7))
successor_node = TreeNode(6)
bst.insert_node(successor_node)
assert_equal(successor(bst.root), successor_node)
def test_successor_returns_none_given_leaf_of_right_most_branch():
from_node = TreeNode(8)
bst = BinarySearchTree(5)
bst.insert_node(TreeNode(3))
bst.insert_node(TreeNode(7))
bst.insert_node(TreeNode(6))
bst.insert_node(from_node)
assert_is_none(successor(from_node))
def test_successor_returns_next_parent_on_right_given_no_right_sub_tree_exists():
bst = BinarySearchTree(5)
successor_node = TreeNode(4)
bst.insert_node(successor_node)
bst.insert_node(TreeNode(2))
from_node = TreeNode(3)
bst.insert_node(from_node)
assert_equal(successor(from_node), successor_node)
def test_successor_returns_parent_given_no_right_sub_tree_exists_parent_on_right():
bst = BinarySearchTree(5)
bst.insert_node(TreeNode(3))
parent = TreeNode(8)
bst.insert_node(parent)
from_node = TreeNode(7)
bst.insert_node(from_node)
bst.insert_node(TreeNode(9))
assert_equal(successor(from_node), parent)
def test_is_binary_search_tree_returns_true_given_valid_bst():
bst = TreeNode(5)
bst.left = TreeNode(3)
bst.right = TreeNode(6)
bst.left.left = TreeNode(2)
bst.left.right = TreeNode(4)
assert_true(is_binary_search_tree(bst))
def test_in_balance_returns_false_when_tree_not_balanced():
root = TreeNode(5)
root.left = TreeNode(3)
root.left.left = TreeNode(2)
root.left.left.left = TreeNode(1)
root.right = TreeNode(6)
assert_false(is_balanced(root))
def build_minimal_tree(arr):
"""Builds a tree of minimal height by recursively partitioning the array
Args:
arr: list from which to build the binary tree
Returns:
Binary Search Tree of minimal height
"""
if len(arr) > 0:
root_index = len(arr) // 2
root = TreeNode(arr[root_index])
root.left = build_minimal_tree(arr[:root_index])
root.right = build_minimal_tree(arr[root_index + 1:])
return root
return None
def test_is_binary_search_tree_returns_false_given_invalid_bst():
bst = TreeNode(5)
bst.left = TreeNode(3)
bst.right = TreeNode(6)
bst.left.left = TreeNode(2)
bst.left.right = TreeNode(
40
) # This node violates the order property since it is greater than the root
assert_false(is_binary_search_tree(bst))
def test_in_balanced_returns_true_when_tree_is_balanced():
root = TreeNode(5)
root.left = TreeNode(3)
root.left.left = TreeNode(2)
root.right = TreeNode(6)
assert_true(is_balanced(root))
def insert(self, data):
"""
Inserts the data and maintains the order property in the tree
Args:
data: data to be inserted in a Tree
"""
self._insert_node(TreeNode(data), self.root)
def test_list_of_depths_populates_from_multi_level_tree():
root = TreeNode(5)
root.left = TreeNode(2)
root.left.left = TreeNode(1)
root.left.right = TreeNode(3)
root.left.right.right = TreeNode(4)
root.right = TreeNode(6)
result = list_of_depths(root)
expected = [
[root],
[root.left, root.right],
[root.left.left, root.left.right],
[root.left.right.right],
]
assert_equal(result, expected)
def test_list_of_depths_returns_populates_correctly_from_stick_tree():
root = TreeNode(5)
root.left = TreeNode(4)
root.left.left = TreeNode(3)
root.left.left.left = TreeNode(2)
root.left.left.left.left = TreeNode(1)
result = list_of_depths(root)
expected = [[root], [root.left], [root.left.left], [root.left.left.left],
[root.left.left.left.left]]
assert_equal(result, expected)
def __init__(self, data):
"""
Args:
data: data to be inserted at the root of the tree
"""
self.root = TreeNode(data)