count-nodes-equal-to-average-of-subtree

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Algorithms

Given the <code>root</code> of a binary tree, return the number of nodes where the value of the node is equal to the average of the values in its subtree.

Note:

<ul>
	<li>The average of <code>n</code> elements is the sum of the <code>n</code> elements divided by <code>n</code> and rounded down to the nearest integer.</li>
	<li>A subtree of <code>root</code> is a tree consisting of <code>root</code> and all of its descendants.</li>
</ul>

&nbsp;
Example 1:
<img src="https://assets.leetcode.com/uploads/2022/03/15/image-20220315203925-1.png" style="width: 300px; height: 212px;" />
<pre>
Input: root = [4,8,5,0,1,null,6]
Output: 5
Explanation: 
For the node with value 4: The average of its subtree is (4 + 8 + 5 + 0 + 1 + 6) / 6 = 24 / 6 = 4.
For the node with value 5: The average of its subtree is (5 + 6) / 2 = 11 / 2 = 5.
For the node with value 0: The average of its subtree is 0 / 1 = 0.
For the node with value 1: The average of its subtree is 1 / 1 = 1.
For the node with value 6: The average of its subtree is 6 / 1 = 6.
</pre>

Example 2:
<img src="https://assets.leetcode.com/uploads/2022/03/26/image-20220326133920-1.png" style="width: 80px; height: 76px;" />
<pre>
Input: root = [1]
Output: 1
Explanation: For the node with value 1: The average of its subtree is 1 / 1 = 1.
</pre>

&nbsp;
Constraints:

<ul>
	<li>The number of nodes in the tree is in the range <code>[1, 1000]</code>.</li>
	<li><code>0 &lt;= Node.val &lt;= 1000</code></li>
</ul>

averageOfSubtree

Count Nodes Equal to Average of Subtree

Maximum Average Subtree

maximum-average-subtree

子树的最大平均值

Insufficient Nodes in Root to Leaf Paths

insufficient-nodes-in-root-to-leaf-paths

根到叶路径上的不足节点

Count Nodes Equal to Sum of Descendants

count-nodes-equal-to-sum-of-descendants

值等于子节点值之和的节点数量

Tree

Depth-First Search

Binary Tree

给你一棵二叉树的根节点 <code>root</code> ，找出并返回满足要求的节点数，要求节点的值等于其 子树 中值的 平均值 。

注意：

<ul>
	<li><code>n</code> 个元素的平均值可以由 <code>n</code> 个元素 求和 然后再除以 <code>n</code> ，并 向下舍入 到最近的整数。</li>
	<li><code>root</code> 的 子树 由 <code>root</code> 和它的所有后代组成。</li>
</ul>

&nbsp;

示例 1：
<img src="https://assets.leetcode.com/uploads/2022/03/15/image-20220315203925-1.png" style="width: 300px; height: 212px;">
<pre>输入：root = [4,8,5,0,1,null,6]
输出：5
解释：
对值为 4 的节点：子树的平均值 (4 + 8 + 5 + 0 + 1 + 6) / 6 = 24 / 6 = 4 。
对值为 5 的节点：子树的平均值 (5 + 6) / 2 = 11 / 2 = 5 。
对值为 0 的节点：子树的平均值 0 / 1 = 0 。
对值为 1 的节点：子树的平均值 1 / 1 = 1 。
对值为 6 的节点：子树的平均值 6 / 1 = 6 。
</pre>

示例 2：
<img src="https://assets.leetcode.com/uploads/2022/03/26/image-20220326133920-1.png" style="width: 80px; height: 76px;">
<pre>输入：root = [1]
输出：1
解释：对值为 1 的节点：子树的平均值 1 / 1 = 1。
</pre>

&nbsp;

提示：

<ul>
	<li>树中节点数目在范围 <code>[1, 1000]</code> 内</li>
	<li><code>0 &lt;= Node.val &lt;= 1000</code></li>
</ul>