Search / Insert into BST
Easy Acceptance 89.54% Points 20
You are given the root of a Binary Search Tree (BST) and an integer key.
- If the key already exists in the BST, return the node containing the key.
- Otherwise, insert the key into the BST while maintaining its properties and return the root of the updated tree.
A Binary Search Tree (BST) follows these rules:
- All values in the left subtree are smaller than the node's value.
- All values in the right subtree are greater than the node's value.
- Both left and right subtrees are also BSTs.
Examples
Example 1
Input: root = [4,2,7,1,3], key = 2
Output: [4,2,7,1,3]
Explanation: The key already exists in the BST, so the tree remains unchanged.
Example 2
Input: root = [4,2,7,1,3], key = 5
Output: [4,2,7,1,3,5]
Explanation: The key 5 is inserted while maintaining the BST property.
Example 3
Input: root = [], key = 8
Output: [8]
Explanation: Since the BST is empty, the new node becomes the root.
Constraints
- 0 = Number of nodes = 105
- -10? = Node.data, key = 10?
Topics
Companies
Added 08 Aug 2026 89.54% acceptance
See how the best solutions work
Approach, complexity and clean code in every language. Sign in to unlock the editorial.
Keep every attempt
Your submissions, results and runtime history live here. Sign in to start your streak.
Ln 1, Col 1Sign in to save your code
50 30 70 20 40 60 80 25
50 30 70 20 40 60 80 25
40 20 60 10 30 50 70 55
40 20 60 10 30 50 70 55
80 50 100 30 60 90 120 75
80 50 100 30 60 90 120 75
Sign in to run your code Run it on the sample cases, then submit against every hidden test.