public class Solution
extends Object
979 - Distribute Coins in Binary Tree\.
Medium
You are given the `root` of a binary tree with `n` nodes where each `node` in the tree has `node.val` coins. There are `n` coins in total throughout the whole tree.
In one move, we may choose two adjacent nodes and move one coin from one node to another. A move may be from parent to child, or from child to parent.
Return _the **minimum** number of moves required to make every node have **exactly** one coin_.
**Example 1:**
**Input:** root = [3,0,0]
**Output:** 2
**Explanation:** From the root of the tree, we move one coin to its left child, and one coin to its right child.
**Example 2:**
**Input:** root = [0,3,0]
**Output:** 3
**Explanation:** From the left child of the root, we move two coins to the root [taking two moves]. Then, we move one coin from the root of the tree to the right child.
**Constraints:**
* The number of nodes in the tree is `n`.
* `1 <= n <= 100`
* `0 <= Node.val <= n`
* The sum of all `Node.val` is `n`.