All Paths in Binary Tree

Given a binary tree, return all root-to-leaf paths in the tree as a list of strings. Each path should be represented as a comma-separated list of node values. Input format: - The first line contains an integer N, the number of nodes in the tree. - The following N lines contain integers representing each node's value in level-order traversal. Use -1 to indicate 'null' nodes. Output format: - Print each path in a new line, sorted lexicographically. Example: Input: 5 1 2 3 -1 -1 4 5 Output: 1,2 1,3,5 1,3,4