public class Solution
extends Object
2385 - Amount of Time for Binary Tree to Be Infected\.
Medium
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:
* The node is currently uninfected.
* The node is adjacent to an infected node.
Return _the number of minutes needed for the entire tree to be infected._
**Example 1:**
**Input:** root = [1,5,3,null,4,10,6,9,2], start = 3
**Output:** 4
**Explanation:** The following nodes are infected during:
- Minute 0: Node 3
- Minute 1: Nodes 1, 10 and 6
- Minute 2: Node 5
- Minute 3: Node 4
- Minute 4: Nodes 9 and 2
It takes 4 minutes for the whole tree to be infected so we return 4.
**Example 2:**
**Input:** root = [1], start = 1
**Output:** 0
**Explanation:** At minute 0, the only node in the tree is infected so we return 0.
**Constraints:**
* The number of nodes in the tree is in the range [1, 105].
* 1 <= Node.val <= 105
* Each node has a **unique** value.
* A node with a value of `start` exists in the tree.