def is_subtree(subroot, root):
if not subroot and not root:
return True
if not subroot or not root:
return False
return is_same_tree(subroot, root) or \
is_subtree(subroot, root.left) or \
is_subtree(subroot, root.right)
def test_nontrivial_true():
# 6
# / \
# 2 8
# / \ / \
# 1 3 7 9
L = [1, 2, 3, 6, 7, 8, 9]
tree = array_to_bst(L)
expected = TreeNode(6)
expected.left = TreeNode(2, left=TreeNode(1), right=TreeNode(3))
expected.right = TreeNode(8, left=TreeNode(7), right=TreeNode(9))
assert is_same_tree(tree, expected)
def test_nontrivial():
# 4 4
# / \ / \
# 2 7 -> 7 2
# / \ / \ / \ / \
# 1 3 6 9 9 6 3 1
tree = TreeNode(4)
tree.left = TreeNode(2, left=TreeNode(1), right=TreeNode(3))
tree.right = TreeNode(7, left=TreeNode(6), right=TreeNode(9))
tree_inv = TreeNode(4)
tree_inv.left = TreeNode(7, left=TreeNode(9), right=TreeNode(6))
tree_inv.right = TreeNode(2, left=TreeNode(3), right=TreeNode(1))
assert is_same_tree(invert(tree), tree_inv)
def test_nontrivial_false():
# 4 4
# / \ / \
# 2 7 != 7 2
# / / \ / \ / \
# 1 6 9 9 6 3 1
tree1 = TreeNode(4)
tree1.left = TreeNode(2, left=TreeNode(1))
tree1.right = TreeNode(7, left=TreeNode(6), right=TreeNode(9))
tree2 = TreeNode(4)
tree2.left = TreeNode(2, left=TreeNode(1), right=TreeNode(3))
tree2.right = TreeNode(7, left=TreeNode(6), right=TreeNode(9))
assert not is_same_tree(tree1, tree2)
def test_nontrivial_true():
# 4 4
# / \ / \
# 2 7 == 2 7
# / \ / \ / \ / \
# 1 3 6 9 1 3 6 9
tree1 = TreeNode(4)
tree1.left = TreeNode(2, left=TreeNode(1), right=TreeNode(3))
tree1.right = TreeNode(7, left=TreeNode(6), right=TreeNode(9))
tree2 = TreeNode(4)
tree2.left = TreeNode(2, left=TreeNode(1), right=TreeNode(3))
tree2.right = TreeNode(7, left=TreeNode(6), right=TreeNode(9))
assert is_same_tree(tree1, tree2)
def test_trivial():
tree = TreeNode(0)
tree_inv = invert(tree)
assert is_same_tree(tree_inv, TreeNode(0))
def test_trivial_true():
tree1 = TreeNode(0)
tree2 = TreeNode(0)
assert is_same_tree(tree1, tree2)
def test_trivial_false():
tree1 = TreeNode(0)
tree2 = TreeNode(1)
assert not is_same_tree(tree1, tree2)