def delete(self, num: int, node: TreeNode = None):
node = node or self.root
if num < node.val:
node.left = self.delete(num, node.left)
elif num > node.val:
node.right = self.delete(num, node.right)
else:
self.size -= 1
if node.left is None and node.right is None:
if self.root == node:
self.root = None
return None
elif node.left is None:
if self.root == node:
self.root = node.right
return node.right
elif node.right is None:
if self.root == node:
self.root = node.left
return node.left
else:
min_node = node.right
while min_node.left:
min_node = min_node.left
node.val = min_node.val
node.right = self.delete(min_node.val, node.right)
return node
def delete(self, node: TreeNode, val: int):
if node is None:
return
if val < node.val:
node.left = self.delete(node.left, val)
if val > node.val:
node.right = self.delete(node.right, val)
if val == node.val:
if node.left and node.right:
predecessor = node.left
while predecessor.right:
predecessor = predecessor.right
node.val = predecessor.val
predecessor.val = val
node.left = self.delete(node.left, val)
elif node.left:
return node.left
elif node.right:
return node.right
else:
return None
return node
def insertNode(self, node: TreeNode, val: int):
if node.val is None or val > node.val:
if node.right:
self.insertNode(node.right, val)
else:
node.right = TreeNode(val)
elif val < node.val:
if node.left:
self.insertNode(node.left, val)
else:
node.left = TreeNode(val)
def helper(left: int, right: int):
if left > right:
return None
mid = (left + right) // 2
root = TreeNode(nums[mid])
root.left = helper(left, mid - 1)
root.right = helper(mid + 1, right)
return root
def rdeserialize(l: List[str]) -> TreeNode:
if l[0] == "None":
l.pop(0)
return None
root = TreeNode(l[0])
l.pop(0)
root.left = rdeserialize(l)
root.right = rdeserialize(l)
return root
def helper(l_idx: int, r_idx: int) -> TreeNode:
if l_idx > r_idx:
return None
val = preorder.pop(0)
node = TreeNode(val)
idx = idx_map[val]
node.left = helper(l_idx, idx - 1)
node.right = helper(idx + 1, r_idx)
return node
def insert(self, node: TreeNode, val: int):
if node is None or node.val == val:
return
if val < node.val:
if node.left:
self.insert(node.left, val)
else:
node.left = TreeNode(val)
if val > node.val:
if node.right:
self.insert(node.right, val)
else:
node.right = TreeNode(val)
def helper(in_left = 0, in_right = len(inorder)) -> TreeNode:
nonlocal pre_idx
if in_left == in_right:
return None
val = preorder[pre_idx]
node = TreeNode(val)
pre_idx += 1
idx = idx_map[val]
node.left = helper(in_left, idx)
node.right = helper(idx + 1, in_right)
return node
def helper(in_left: int, in_right: int) -> TreeNode:
if in_left > in_right:
return None
# pick up the last element as a root
val = postorder.pop()
root = TreeNode(val)
# root splits inorder list
# into left and right subtree
index = idx_map[val]
# build right subtree
root.right = helper(index + 1, in_right)
# build left subtree
root.left = helper(in_left, index - 1)
return root