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leetcode-problemset/算法题(国外版)/minimum-number-of-removals-to-make-mountain-array.html
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<p>You may recall that an array <code>arr</code> is a <strong>mountain array</strong> if and only if:</p>
<ul>
<li><code>arr.length &gt;= 3</code></li>
<li>There exists some index <code>i</code> (<strong>0-indexed</strong>) with <code>0 &lt; i &lt; arr.length - 1</code> such that:
<ul>
<li><code>arr[0] &lt; arr[1] &lt; ... &lt; arr[i - 1] &lt; arr[i]</code></li>
<li><code>arr[i] &gt; arr[i + 1] &gt; ... &gt; arr[arr.length - 1]</code></li>
</ul>
</li>
</ul>
<p>Given an integer array <code>nums</code>, return <em>the <strong>minimum</strong> number of elements to remove to make </em><code>nums<em></em></code><em> </em><em>a <strong>mountain array</strong>.</em></p>
<p>&nbsp;</p>
<p><strong>Example 1:</strong></p>
<pre>
<strong>Input:</strong> nums = [1,3,1]
<strong>Output:</strong> 0
<strong>Explanation:</strong> The array itself is a mountain array so we do not need to remove any elements.
</pre>
<p><strong>Example 2:</strong></p>
<pre>
<strong>Input:</strong> nums = [2,1,1,5,6,2,3,1]
<strong>Output:</strong> 3
<strong>Explanation:</strong> One solution is to remove the elements at indices 0, 1, and 5, making the array nums = [1,5,6,3,1].
</pre>
<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>
<ul>
<li><code>3 &lt;= nums.length &lt;= 1000</code></li>
<li><code>1 &lt;= nums[i] &lt;= 10<sup>9</sup></code></li>
<li>It is guaranteed that you can make a mountain array out of <code>nums</code>.</li>
</ul>