def helper(self, nums):
if len(nums) == 0:
return None
pivot = len(nums) // 2
root = TreeNode(nums[pivot])
root.left = self.helper(nums[:pivot])
root.right = self.helper(nums[pivot + 1:])
return root
def test_generateTrees3():
n = 1
expect = sorted([TreeNode.integerListToString(nums) for nums in [[1]]])
actual = solution.generateTrees(n)
assert len(actual) == len(expect)
actual = sorted([
TreeNode.integerListToString(nums)
for nums in [TreeNode.treeToList(node) for node in actual]
])
assert actual == expect
def buildTree(self, preorder: List[int], inorder: List[int]) -> TreeNode:
if preorder is None or len(preorder) != len(inorder) or len(preorder) == 0:
return None
i = 0
while i < len(inorder) and inorder[i] != preorder[0]:
i += 1
root = TreeNode(preorder[0])
root.left = self.buildTree(preorder[1:i + 1], inorder[0:i])
root.right = self.buildTree(preorder[i + 1:], inorder[i + 1:])
return root
def flatten(self, root: TreeNode) -> None:
"""
Do not return anything, modify root in-place instead.
"""
tail = TreeNode(0)
queue = [root] if root else []
while queue:
node = queue.pop()
if node.right:
queue.append(node.right)
if node.left:
queue.append(node.left)
node.left = None
tail.right = node
tail = tail.right
def test_generateTrees1():
root = TreeNode.stringToTreeNode(
"[5, 4, 8, 11, null, 13, 4, 7, 2, null, null, 5, 1]")
sum = 22
expect = [[5, 8, 4, 5], [5, 4, 11, 2]]
actual = solution.pathSum(root, sum)
assert sorted(actual) == sorted(expect)
def generate(self, start, end):
if start > end:
return [None]
if start == end:
return [TreeNode(start)]
result = []
for num in range(start, end + 1):
lefts = self.generate(start, num - 1)
rights = self.generate(num + 1, end)
for left in lefts:
for right in rights:
root = TreeNode(num)
root.left = left
root.right = right
result.append(root)
return result
def test_iterator():
root = TreeNode.stringToTreeNode("[7,3,15,null,null,9,20]")
iterator = BSTIterator(root)
assert iterator.next() == 3
assert iterator.next() == 7
assert iterator.hasNext()
assert iterator.next() == 9
assert iterator.hasNext()
assert iterator.next() == 15
assert iterator.hasNext()
assert iterator.next() == 20
assert not iterator.hasNext()
def test_generateTrees1():
root = TreeNode.stringToTreeNode("[3,9,20,null,null,15,7]")
expect = [[3], [20, 9], [15, 7]]
actual = solution.zigzagLevelOrder(root)
assert actual == expect
def test_generateTrees2():
root = TreeNode.stringToTreeNode("[]")
expect = []
actual = solution.zigzagLevelOrder(root)
assert actual == expect
def test_generateTrees3():
root = TreeNode.stringToTreeNode("[1,2,3,4,null,null,5]")
expect = [[1], [3, 2], [4, 5]]
actual = solution.zigzagLevelOrder(root)
assert actual == expect
def test_isValidBST5():
root = TreeNode.stringToTreeNode("[10,5,15,null,null,6,20]")
actual = solution.isValidBST(root)
assert not actual
def test_isValidBST1():
root = TreeNode.stringToTreeNode("[2,1,3]")
actual = solution.isValidBST(root)
assert actual
def test_sumNumbers1():
root = TreeNode.stringToTreeNode('[1,2,3]')
expect = 25
actual = solution.sumNumbers(root)
assert actual == expect
def test_isValidBST4():
root = TreeNode.stringToTreeNode("[0,null,-1]")
actual = solution.isValidBST(root)
assert not actual
def test_sumNumbers2():
root = TreeNode.stringToTreeNode('[4,9,0,5,1]')
expect = 1026
actual = solution.sumNumbers(root)
assert actual == expect
def test_buildTree1():
preorder = [3, 9, 20, 15, 7]
inorder = [9, 3, 15, 20, 7]
expect = TreeNode.stringToTreeNode("[3,9,20,null,null,15,7]")
actual = solution.buildTree(preorder, inorder)
assert TreeNode.isSame(actual, expect)
def test_buildTree1():
head = ListNode.stringToListNode("[-10,-3,0,5,9]")
expect = TreeNode.stringToTreeNode("[0,-3,9,-10,null,5]")
actual = solution.sortedListToBST(head)
assert TreeNode.isSame(actual, expect)
def test_buildTree1():
root = TreeNode.stringToTreeNode("[1,2,5,3,4,null,6]")
expect = TreeNode.stringToTreeNode(
"[1,null,2,null,3,null,4,null,5,null,6]")
solution.flatten(root)
assert TreeNode.isSame(root, expect)
def test_buildTree2():
root = TreeNode.stringToTreeNode("[]")
expect = TreeNode.stringToTreeNode("[]")
solution.flatten(root)
assert TreeNode.isSame(root, expect)
def test_buildTree1():
inorder = [9, 3, 15, 20, 7]
postorder = [9, 15, 7, 20, 3]
expect = TreeNode.stringToTreeNode("[3,9,20,null,null,15,7]")
actual = solution.buildTree(inorder, postorder)
assert TreeNode.isSame(actual, expect)
def test_sumNumbers3():
root = TreeNode.stringToTreeNode('[]')
expect = 0
actual = solution.sumNumbers(root)
assert actual == expect
def test_buildTree2():
preorder = []
inorder = [9]
expect = TreeNode.stringToTreeNode("[]")
actual = solution.buildTree(preorder, inorder)
assert TreeNode.isSame(actual, expect)
def test_preorderTraversal1():
root = TreeNode.stringToTreeNode("[1,null,2,3]")
expect = [1, 2, 3]
actual = solution.preorderTraversal(root)
assert actual == expect
def test_inorderTraversal2():
root = TreeNode.stringToTreeNode("[1,2,3]")
expect = [2, 1, 3]
actual = solution.inorderTraversal(root)
assert actual == expect
def test_sumNumbers4():
root = TreeNode.stringToTreeNode('[1, null, 2]')
expect = 12
actual = solution.sumNumbers(root)
assert actual == expect
def test_preorderTraversal3():
root = TreeNode.stringToTreeNode("[]")
expect = []
actual = solution.preorderTraversal(root)
assert actual == expect
def test_isValidBST2():
root = TreeNode.stringToTreeNode("[5,1,4,null,null,3,6]")
actual = solution.isValidBST(root)
assert not actual
def test_rightSideView1():
root = TreeNode.stringToTreeNode("[1,2,3,null,5,null,4]")
expect = [1, 3, 4]
actual = solution.rightSideView(root)
assert actual == expect
def test_isValidBST3():
root = TreeNode.stringToTreeNode("[1,1,1]")
actual = solution.isValidBST(root)
assert not actual
