1. Tree Basics and Traversals
·      Implement a Binary Tree
·      Preorder Traversal (Recursive and Iterative)
·      Inorder Traversal (Recursive and Iterative)
·      Postorder Traversal (Recursive and Iterative)
·      Level Order Traversal (BFS)
·      Reverse Level Order Traversal
·      Spiral/Zigzag Level Order Traversal
·      Boundary Traversal of a Binary Tree
·      Diagonal Traversal of a Binary Tree
·      Vertical Order Traversal of a Binary Tree
 
 2. Binary Tree Construction Problems
·      Construct a Binary Tree from Inorder and Preorder Traversal
·      Construct a Binary Tree from Inorder and Postorder Traversal
·      Construct a Binary Tree from Level Order and Inorder Traversal
·      Construct a Special Tree from Inorder Traversal (Tree with Only One Child Nodes)
·      Construct a Full Binary Tree from Preorder and Postorder Traversal
·      Construct a Binary Tree from its Mirror Image
·      Convert a Binary Tree to its Mirror Tree
·      Convert a Binary Tree to a Doubly Linked List
·      Construct a Threaded Binary Tree
·      Build a Tree from Inorder and Level Order Traversal
 
 3. Tree Properties and Analysis
·      Find the Height of a Binary Tree
·      Find the Depth of a Given Node
·      Check if a Tree is Symmetric
·      Check if Two Trees are Identical
·      Diameter of a Binary Tree
·      Check if a Binary Tree is Balanced (Height Balanced)
·      Check if a Binary Tree is a Sum Tree
·      Maximum Path Sum in a Binary Tree
·      Check if a Binary Tree is Perfect
·      Check if a Binary Tree is Complete
 
 4. Tree Modification and Manipulation
·      Convert a Binary Tree to a Sum Tree
·      Convert a Binary Tree to a Child-Sum Property Tree
·      Convert a Binary Tree to a Doubly Linked List
·      Convert a Binary Tree into a Circular Doubly Linked List
·      Convert a Binary Tree to a Threaded Binary Tree
·      Flatten a Binary Tree to a Linked List
·      Convert a Binary Tree to a List of Levels
·      Convert a Binary Tree to an Inverted Tree
·      Add All Greater Values to Every Node in a Binary Search Tree (BST)
·      Merge Two Binary Trees
 
 5. Binary Search Tree (BST) Problems
·      Insert a Node in a BST
·      Delete a Node in a BST
·      Search for a Node in a BST
·      Find the Minimum and Maximum Value in a BST
·      Find the Inorder Successor and Predecessor in a BST
·      Check if a Given Tree is a BST
·      Convert a BST to a Greater Sum Tree
·      Lowest Common Ancestor (LCA) in a BST
·      Check if a BST is Height Balanced
·      Merge Two BSTs into a Balanced BST
 
 6. Tree Views
·      Left View of a Binary Tree
·      Right View of a Binary Tree
·      Top View of a Binary Tree
·      Bottom View of a Binary Tree
·      Print All Leaf Nodes from Left to Right
·      Print All Leaf Nodes from Right to Left
·      Boundary View of a Binary Tree
·      Print the Longest Path in a Binary Tree
·      Print Nodes at Distance K from the Root
·      Print Nodes at Distance K from a Given Node
 
7. Tree Recursive Problems
·      Print All Ancestors of a Given Node
·      Print All Paths from Root to Leaf
·      Print the Path from Root to a Given Node
·      Find the Kth Smallest Element in a BST
·      Find the Kth Largest Element in a BST
·      Find the Lowest Common Ancestor (LCA) in a Binary Tree
·      Count Leaf Nodes in a Binary Tree
·      Count Non-Leaf Nodes in a Binary Tree
·      Count Nodes with Exactly One Child in a Binary Tree
·      Count Nodes with Two Children in a Binary Tree
 
 8. Tree Algorithms and Techniques
·      Morris Traversal (Inorder and Preorder without Recursion and Stack)
·      Threaded Binary Tree Traversal
·      Finding the Maximum Width of a Binary Tree
·      Serialize and Deserialize a Binary Tree
·      Check if a Binary Tree is Subtree of Another Tree
·      Find the Largest BST in a Binary Tree
·      Find All Nodes at Distance K in a Binary Tree
·      Convert a Binary Tree to a Circular Doubly Linked List
·      Inorder Successor in a BST without Using Parent Pointer
·      Flatten a Binary Tree into a List of Levels
 
 9. Tree-Based Dynamic Programming
·      Maximum Path Sum in a Binary Tree
·      Maximum Sum of Nodes without Adjacent Nodes
·      Diameter of a Binary Tree using DP
·      Largest Independent Set Problem in a Binary Tree
·      House Robber Problem (Binary Tree Version)
·      Longest Path Between Any Two Nodes
·      Count Number of Subtrees with a Given Sum
·      Find the Longest Consecutive Sequence Path in a Binary Tree
·      Check if a Tree can be Partitioned into Two Trees with Equal Sum
·      Count Number of Unique BSTs (Catalan Number)
 
 10. Tree Miscellaneous Problems
·      Check if a Tree is a Mirror of Itself (Symmetric)
·      Convert Sorted Array to a Balanced BST
·      Convert Sorted Linked List to a Balanced BST
·      Print Nodes in the Topological Order of a Binary Tree
·      Sum of All Nodes in a Binary Tree
·      Sum of All Left Leaves in a Binary Tree
·      Sum of All Right Leaves in a Binary Tree
·      Print the Vertical Sum of a Binary Tree
·      Find All Duplicate Subtrees in a Binary Tree
·      Find the Maximum Sum Subtree in a Binary Tree