1
0
mirror of https://gitee.com/coder-xiaomo/leetcode-problemset synced 2025-01-11 02:58:13 +08:00
Code Issues Projects Releases Wiki Activity GitHub Gitee
leetcode-problemset/leetcode-cn/problem (English)/叶值的最小代价生成树(English) [minimum-cost-tree-from-leaf-values].html
2022-03-29 12:43:11 +08:00

38 lines
1.6 KiB
HTML

<p>Given an array <code>arr</code> of positive integers, consider all binary trees such that:</p>
<ul>
<li>Each node has either <code>0</code> or <code>2</code> children;</li>
<li>The values of <code>arr</code> correspond to the values of each <strong>leaf</strong> in an in-order traversal of the tree.</li>
<li>The value of each non-leaf node is equal to the product of the largest leaf value in its left and right subtree, respectively.</li>
</ul>
<p>Among all possible binary trees considered, return <em>the smallest possible sum of the values of each non-leaf node</em>. It is guaranteed this sum fits into a <strong>32-bit</strong> integer.</p>
<p>A node is a <strong>leaf</strong> if and only if it has zero children.</p>
<p>&nbsp;</p>
<p><strong>Example 1:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2021/08/10/tree1.jpg" style="width: 500px; height: 169px;" />
<pre>
<strong>Input:</strong> arr = [6,2,4]
<strong>Output:</strong> 32
<strong>Explanation:</strong> There are two possible trees shown.
The first has a non-leaf node sum 36, and the second has non-leaf node sum 32.
</pre>
<p><strong>Example 2:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2021/08/10/tree2.jpg" style="width: 224px; height: 145px;" />
<pre>
<strong>Input:</strong> arr = [4,11]
<strong>Output:</strong> 44
</pre>
<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>
<ul>
<li><code>2 &lt;= arr.length &lt;= 40</code></li>
<li><code>1 &lt;= arr[i] &lt;= 15</code></li>
<li>It is guaranteed that the answer fits into a <strong>32-bit</strong> signed integer (i.e., it is less than 2<sup>31</sup>).</li>
</ul>