Lowest Common Ancestor of a Binary Tree

Given a binary tree serialized as a level-order array with `-1` denoting null nodes, find the lowest common ancestor (LCA) of two given node values `p` and `q`. The lowest common ancestor is defined between two nodes `p` and `q` as the lowest node in `T` that has both `p` and `q` as descendants (where we allow a node to be a descendant of itself). ### Constraints - Number of nodes in the tree is in range `[2, 10^5]`. - `-10^9 <= Node.val <= 10^9` - All `Node.val` are unique. - `p != q` - `p` and `q` exist in the tree. ### Input Format First line contains integer `n` representing number of serialized tokens. Second line contains space-separated integers representing level-order binary tree (-1 for null). Third line contains two space-separated integers `p` and `q`. ### Output Format Print the integer value of the lowest common ancestor node.