leetcode-problemset/leetcode-cn/problem (Chinese)/根到叶路径上的不足节点 [insufficient-nodes-in-root-to-leaf-paths].html

<p>给定一棵二叉树的根 <code>root</code>，请你考虑它所有&nbsp;<strong>从根到叶的路径</strong>：从根到任何叶的路径。（所谓一个叶子节点，就是一个没有子节点的节点）</p>

<p>假如通过节点 <code>node</code> 的每种可能的 &ldquo;根-叶&rdquo; 路径上值的总和全都小于给定的 <code>limit</code>，则该节点被称之为「不足节点」，需要被删除。</p>

<p>请你删除所有不足节点，并返回生成的二叉树的根。</p>

<p>&nbsp;</p>

<p><strong>示例 1：</strong></p>

<pre><strong><img alt="" src="https://assets.leetcode-cn.com/aliyun-lc-upload/uploads/2019/06/08/insufficient-1.png" style="height: 200px; width: 482px;">
输入：</strong>root = [1,2,3,4,-99,-99,7,8,9,-99,-99,12,13,-99,14], limit = 1
<strong><img alt="" src="https://assets.leetcode-cn.com/aliyun-lc-upload/uploads/2019/06/08/insufficient-2.png" style="height: 200px; width: 258px;">
输出：</strong>[1,2,3,4,null,null,7,8,9,null,14]
</pre>

<p><strong>示例 2：</strong></p>

<pre><strong><img alt="" src="https://assets.leetcode-cn.com/aliyun-lc-upload/uploads/2019/06/08/insufficient-3.png" style="height: 200px; width: 292px;">
输入：</strong>root = [5,4,8,11,null,17,4,7,1,null,null,5,3], limit = 22
<strong><img alt="" src="https://assets.leetcode-cn.com/aliyun-lc-upload/uploads/2019/06/08/insufficient-4.png" style="height: 200px; width: 264px;">
输出：</strong>[5,4,8,11,null,17,4,7,null,null,null,5]</pre>

<p><strong>示例 3：</strong></p>

<pre><strong><img alt="" src="https://assets.leetcode-cn.com/aliyun-lc-upload/uploads/2019/06/08/insufficient-5.png" style="height: 100px; width: 140px;">
输入：</strong>root = [5,-6,-6], limit = 0<strong>
输出：</strong>[]</pre>

<p>&nbsp;</p>

<p><strong>提示：</strong></p>

<ol>
	<li>给定的树有&nbsp;<code>1</code>&nbsp;到&nbsp;<code>5000</code>&nbsp;个节点</li>
	<li><code>-10^5&nbsp;&lt;= node.val &lt;= 10^5</code></li>
	<li><code>-10^9 &lt;= limit&nbsp;&lt;= 10^9</code></li>
</ol>

<p>&nbsp;</p>