class Solution1:
def isSymmetric(self, root: TreeNode) -> bool:
if not root:
return True
stack = [(root.left, root.right)]
while stack:
p, q = stack.pop()
if not p and not q:
continue
if not p or not q or p.val != q.val:
return False
stack.append((p.left, q.right))
stack.append((p.right, q.left))
return True
@pytest.mark.parametrize("args,expected", [
(TreeNode.initTreeSimple([1, 2, 2], [(0, 1)], [(0, 2)]), True),
(TreeNode.initTreeSimple([1, None, 2, 4], [(2, 3)], [(0, 2)]), False),
])
def test_solutions(args, expected):
assert Solution().isSymmetric(args) == expected
assert Solution1().isSymmetric(args) == expected
if __name__ == '__main__':
pytest.main(["-q", "--color=yes", "--capture=no", __file__])
return isValidRecursive(root)
class Solution2(object):
def isValidBST(self, root):
return self.isValidBSTRecu(root, float("-inf"), float("inf"))
def isValidBSTRecu(self, root, low, high):
if root is None:
return True
return low < root.val < high \
and self.isValidBSTRecu(root.left, low, root.val) \
and self.isValidBSTRecu(root.right, root.val, high)
@pytest.mark.parametrize("args,expected", [
(TreeNode.initTreeSimple([2, 1, 3], [(1, 0)], [(1, 2)]), True),
(TreeNode.initTreeSimple([1, None, 2, 3], [(2, 3)], [(0, 2)]), False),
(TreeNode.initTreeSimple([3, 9, 20, None, None, 15, 7], [(0, 1), (2, 5)],
[(0, 2), (2, 6)]), False),
])
def test_solutions(args, expected):
assert Solution().isValidBST(args) == expected
assert Solution2().isValidBST(args) == expected
if __name__ == '__main__':
pytest.main(["-q", "--color=yes", "--capture=no", __file__])