def test_post_order_traversal():
for nodes, expected_result in [
(
(
8,
[(4,
[2, 6]),
(10,
[None, 20])]
),
"2->6->4->20->10->8"
),
(
(1, ), "1"
),
(
(1, [2]), "2->1"
),
(
(1, [None, 2]), "2->1"
),
]:
result = []
def visit(node: Node) -> None:
result.append(node.val)
bt = BinaryTree(BinaryTree.build(nodes))
bt.post_order(visit)
result = "->".join([str(val) for val in result])
assert result == expected_result, "{} != {}".format(result, expected_result)
def test_insert_method_for_BT():
bt = BinaryTree(BinaryTree.build(SIMPLE_TREE))
for use_case, *expected_result in [
(1, True, True, """
-- 8
| |-- 4
| | |-- 2
| | | |-- 1
| | |-- 6
| |-- 10
| | |-- 20"""),
(0, True, True, """
-- 8
| |-- 4
| | |-- 2
| | | |-- 1
| | | |-- 0
| | |-- 6
| |-- 10
| | |-- 20"""),
(3, True, True, """
-- 8
| |-- 4
| | |-- 2
| | | |-- 1
| | | | |-- 3
| | | |-- 0
| | |-- 6
| |-- 10
| | |-- 20"""),
(8, False, True, """
-- 8
| |-- 4
| | |-- 2
| | | |-- 1
| | | | |-- 3
| | | |-- 0
| | |-- 6
| |-- 10
| | |-- 20"""),
]:
insert_result, find_result, tree_repr = expected_result
result = bt.insert(use_case)
assert result == insert_result, "{} != {}".format(result, insert_result)
result = bt.find(use_case)
assert result == find_result, "{} != {}".format(result, find_result)
assert str(bt) == tree_repr, "{} != {}".format(str(bt), tree_repr)
return None
if len(node.nodes) > 1 and node.nodes[1] is not None:
return find_right_left_most_node(node)
# we need to check the parent
# we may be the left child, thus we need to return parent
# we may be the right child, we need to go to grandpa
while node.parent and node.parent.nodes[0] != node:
node = node.parent
return node.parent
bt = BinaryTree(BinaryTree.build((8, [(4, [2, 6]), (10, [None, 20])])))
for use_case, expected_result in [
(4, 6),
(6, 8),
(10, 20),
(20, None),
]:
node = bt.find_node(use_case)
result = find_successor(node)
if not expected_result:
assert result is None, "{} is not None".format(result)
else:
if result is None:
assert False, "None != {}".format(expected_result)
if root.left == None and root.right == None:
return 1
return 1 + max(height(root.left), height(root.right))
def diameter(root):
if not root:
return 0
h1 = height(root.left)
h2 = height(root.right)
dl = diameter(root.left)
dr = diameter(root.right)
return max(h1+h2, max(dl, dr))
def optimizedDiameter(root):
if not root:
return [0, 0]
left = optimizedDiameter(root.left)
right = optimizedDiameter(root.right)
height_till_now = max(left[0], right[0]) + 1
diameter_till_now = max(left[0] + right[0], max(left[1], right[1]))
return [height_till_now, diameter_till_now]
t = BinaryTree()
t.build([1, 2, 3, 4, 5])
print("Diameter: ", diameter(t.root))
print("Diameter: ", optimizedDiameter(t.root)[1])
from tree import BinaryTree
import sys
# Note: if duplicate is not allowed then remove =
def valid_bst(root):
def helper(root, left_min, right_max):
if not root:
return True
if (left_min <= root.val and root.val <= right_max
and helper(root.left, left_min, root.val)
and helper(root.right, root.val, right_max)):
return True
return False
return helper(root, -sys.maxsize, sys.maxsize)
if __name__ == "__main__":
arr = [5, 4, 6, None, None, 3, 7]
t = BinaryTree()
t.build(arr)
ans = valid_bst(t.root)
print(ans)
# if there is one NULL in left or then take non null value
# if both are non null then it is the lca
# if both values are present into the same subtree then top will be the lca.
def lca(root, p, q):
if not root or root.val == p.val or root.val == q.val:
return root
print(root.val, end="->")
left = lca(root.left, p, q)
right = lca(root.right, p, q)
if left and right:
# one element is in left side and other is no right side.
return root
elif left:
# element is left
return left
else:
# not in left then either right or both none
return right
t = BinaryTree()
t.build([3, 5, 1, 6, 2, 0, 8, None, None, 7, 4])
p = t.search(5)
q = t.search(4)
lca_node = lca(t.root, p, q)
print(f"LCA: {lca_node.val}")
def test_is_not_balanced():
for nodes in IMBALANCED_TREES:
bt = BinaryTree(BinaryTree.build(nodes))
assert not bt.is_balanced, "Tree {} is balanced".format(bt)
def test_that_a_tree_is_not_perfect():
for raw_nodes in IMPERFECT_TREES:
bt = BinaryTree(BinaryTree.build(raw_nodes))
assert not bt.is_perfect, "Tree {} is perfect".format(bt)
def test_that_a_tree_is_full():
for raw_nodes in NOT_FULL_TREES:
bt = BinaryTree(BinaryTree.build(raw_nodes))
assert not bt.is_full, "Tree {} is full".format(bt)
def test_that_a_tree_is_incompleted():
for raw_nodes in INCOMPLETE_TREES:
bt = BinaryTree(BinaryTree.build(raw_nodes))
assert not bt.is_complete, "Tree {} is complete".format(bt)
__helper(root.right, l+1)
__helper(root, 0)
def right_view(root, h):
visited = [0]*h
def __helper(root, l):
if not root:
return
if not visited[l]:
print(root.val, end=" ")
visited[l] = 1
__helper(root.right, l+1)
__helper(root.left, l+1)
__helper(root, 0)
t = BinaryTree()
t.build([1,2,3,None,5,None,4])
print("Left: ", end=" ")
left_view(t.root, t.height())
print("\nRight: ", end=" ")
right_view(t.root, t.height())