You are given the root of a binary tree with unique values, and an integer start. At minute 0, an infection starts from the node with value start.
Each minute, a node becomes infected if:
Return the number of minutes needed for the entire tree to be infected.
Note: In a binary tree, a node is adjacent to its parent and its children. The infection spreads in all directions — not just downward.
1 <= number of nodes <= 10^51 <= Node.val <= 10^5start exists in the tree.root = [1,5,3,null,4,10,6,9,2], start = 34root = [1], start = 10