Tree/Graph Traversal:

• Find the path between two nodes in a binary tree.
• Calculate the maximum path sum in a binary tree.
• Determine the number of islands in a grid or tree structure.

Build a prompting engine that can improve itself without any ongoing upkeep.

Strings & Arrays:

• Reverse a string using recursion or find the first non-repeated character.
• Find the longest consecutive subsequence in an array.
• Find the median of two sorted arrays.