Minimum Depth of Binary Tree

Given a binary tree, find its minimum depth. The **minimum depth** is the number of nodes along the shortest path from the root node down to the nearest leaf node. Note: A leaf is a node with no children. ### Constraints - The number of nodes in the tree is in the range `[0, 10^5]`. - `-1000 <= Node.val <= 1000` ### Input Format A single line containing space-separated integers representing the tree in level-order (-1 for null). ### Output Format Print a single integer representing the minimum depth.