1. Given a binary tree, find the number of unique paths from the top-left to the bottom-right.
2. Given a string, write a function to print all permutations of the string.
3. How would you approach the relaunch of Zepto Pass, and what tracking methods would you implement to measure its success?
4. Write an SQL query.
5. Given a binary tree, a target node, and an integer K, find all nodes that are K distances from the target node.