Level: Advanced
1. Serialize and Deserialize N-ary Tree: Serialize and deserialize an N-ary tree.
2. Maximum Product of Splitted Binary Tree: Given a binary tree, split it into two subtrees such that the product of the sums of the subtrees is maximized.
3. Count Complete Tree Nodes: Count the number of nodes in a complete binary tree.
4. Binary Tree Vertical Order Traversal: Perform a vertical order traversal of a binary tree.
5. Smallest Subtree with all the Deepest Nodes: Find the smallest subtree such that all the deepest nodes in the original tree are there.
6. Longest ZigZag Path in a Binary Tree: Find the length of the longest zigzag path in a binary tree.
7. Binary Tree Maximum Path Sum: Find the maximum path sum between any two nodes in a binary tree.
8. Construct Binary Tree from Preorder and Inorder Traversal: Construct a binary tree from preorder and inorder traversal sequences.
9. Binary Tree Maximum Width of Binary Tree: Find the maximum width of a binary tree.