Project Notes

Binary Tree Maximum Path Sum

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Description

tab: English
 
<p>A <strong>path</strong> in a binary tree is a sequence of nodes where each pair of adjacent nodes in the sequence has an edge connecting them. A node can only appear in the sequence <strong>at most once</strong>. Note that the path does not need to pass through the root.</p>
 
<p>The <strong>path sum</strong> of a path is the sum of the node&#39;s values in the path.</p>
 
<p>Given the <code>root</code> of a binary tree, return <em>the maximum <strong>path sum</strong> of any <strong>non-empty</strong> path</em>.</p>
 
<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2020/10/13/exx1.jpg" style="width: 322px; height: 182px;" />
<pre>
<strong>Input:</strong> root = [1,2,3]
<strong>Output:</strong> 6
<strong>Explanation:</strong> The optimal path is 2 -&gt; 1 -&gt; 3 with a path sum of 2 + 1 + 3 = 6.
</pre>
 
<p><strong class="example">Example 2:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2020/10/13/exx2.jpg" />
<pre>
<strong>Input:</strong> root = [-10,9,20,null,null,15,7]
<strong>Output:</strong> 42
<strong>Explanation:</strong> The optimal path is 15 -&gt; 20 -&gt; 7 with a path sum of 15 + 20 + 7 = 42.
</pre>
 
<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>
 
<ul>
	<li>The number of nodes in the tree is in the range <code>[1, 3 * 10<sup>4</sup>]</code>.</li>
	<li><code>-1000 &lt;= Node.val &lt;= 1000</code></li>
</ul>
 
 
 
---
 
[submissions](https://leetcode.com/problems/binary-tree-maximum-path-sum/submissions/) | [solutions](https://leetcode.com/problems/binary-tree-maximum-path-sum/solutions/)
 
 
tab: 中文
 
<p>二叉树中的<strong> 路径</strong> 被定义为一条节点序列，序列中每对相邻节点之间都存在一条边。同一个节点在一条路径序列中 <strong>至多出现一次</strong> 。该路径<strong> 至少包含一个 </strong>节点，且不一定经过根节点。</p>
 
<p><strong>路径和</strong> 是路径中各节点值的总和。</p>
 
<p>给你一个二叉树的根节点 <code>root</code> ，返回其 <strong>最大路径和</strong> 。</p>
 
<p>&nbsp;</p>
 
<p><strong>示例 1：</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2020/10/13/exx1.jpg" style="width: 322px; height: 182px;" />
<pre>
<strong>输入：</strong>root = [1,2,3]
<strong>输出：</strong>6
<strong>解释：</strong>最优路径是 2 -&gt; 1 -&gt; 3 ，路径和为 2 + 1 + 3 = 6</pre>
 
<p><strong>示例 2：</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2020/10/13/exx2.jpg" />
<pre>
<strong>输入：</strong>root = [-10,9,20,null,null,15,7]
<strong>输出：</strong>42
<strong>解释：</strong>最优路径是 15 -&gt; 20 -&gt; 7 ，路径和为 15 + 20 + 7 = 42
</pre>
 
<p>&nbsp;</p>
 
<p><strong>提示：</strong></p>
 
<ul>
	<li>树中节点数目范围是 <code>[1, 3 * 10<sup>4</sup>]</code></li>
	<li><code>-1000 &lt;= Node.val &lt;= 1000</code></li>
</ul>
 
 
 
---
 
[提交记录](https://leetcode.cn/problems/binary-tree-maximum-path-sum/submissions/) | [题解](https://leetcode.cn/problems/binary-tree-maximum-path-sum/solution/)

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