701. Insert into a Binary Search Tree
Category: /leetcodeYou are given the root node of a binary search tree (BST) and a value to insert into the tree. Return the root node of the BST after the insertion. It is guaranteed that the new value does not exist in the original BST.
Notice that there may exist multiple valid ways for the insertion, as long as the tree remains a BST after insertion. You can return any of them.
Solution:
def insertIntoBST(self, root: TreeNode, val: int) -> TreeNode:
if not root: return TreeNode(val)
if val < root.val:
root.left = self.insertIntoBST(root.left, val)
elif val > root.val:
root.right = self.insertIntoBST(root.right, val)
return root
Iteration
def insertIntoBST(self, root: TreeNode, val: int) -> TreeNode:
node = root
while node:
if val > node.val:
# insert right leaf
if not node.right:
node.right = TreeNode(val)
return root
else:
node = node.right
else:
# insert left leaf
if not node.left:
node.left = TreeNode(val)
return root
else:
node = node.left
return TreeNode(val)
