Practice Problems
1. Easy Level​
- Binary Tree Inorder Traversal
- Binary Tree Preorder Traversal
- Binary Tree Postorder Traversal
- Maximum Depth of Binary Tree
- Same Tree
- Invert Binary Tree
- Symmetric Tree
- Path Sum
- Count Complete Tree Nodes
- Average of Levels in Binary Tree
- Minimum Absolute Difference in BST
- Search in a Binary Search Tree
- Leaf-Similar Trees
2. Medium Level​
- Construct Binary Tree from Preorder and Inorder Traversal
- Construct Binary Tree from Inorder and Postorder Traversal
- Populating Next Right Pointers in Each Node II
- Flatten Binary Tree to Linked List
- Sum Root to Leaf Numbers
- Binary Search Tree Iterator
- Lowest Common Ancestor of a Binary Tree
- Binary Tree Right Side View
- Binary Tree Level Order Traversal
- Binary Tree Zigzag Level Order Traversal
- Kth Smallest Element in a BST
- Validate Binary Search Tree
- Count Good Nodes in Binary Tree
- Path Sum III -Delete Node in a BST