leetcode-problemset/leetcode-cn/problem (Chinese)/求出数组中最大序列值 [find-the-maximum-sequence-value-of-array].html

<p>给你一个整数数组&nbsp;<code>nums</code>&nbsp;和一个 <strong>正</strong>&nbsp;整数&nbsp;<code>k</code>&nbsp;。</p>

<p>定义长度为 <code>2 * x</code>&nbsp;的序列 <code>seq</code>&nbsp;的 <strong>值</strong>&nbsp;为：</p>

<ul>
	<li><code>(seq[0] OR seq[1] OR ... OR seq[x - 1]) XOR (seq[x] OR seq[x + 1] OR ... OR seq[2 * x - 1])</code>.</li>
</ul>

<p>请你求出 <code>nums</code>&nbsp;中所有长度为 <code>2 * k</code>&nbsp;的 <span data-keyword="subsequence-array">子序列</span> 的 <strong>最大值</strong>&nbsp;。</p>

<p>&nbsp;</p>

<p><strong class="example">示例 1：</strong></p>

<div class="example-block">
<p><span class="example-io"><b>输入：</b>nums = [2,6,7], k = 1</span></p>

<p><span class="example-io"><b>输出：</b>5</span></p>

<p><strong>解释：</strong></p>

<p>子序列&nbsp;<code>[2, 7]</code>&nbsp;的值最大，为&nbsp;<code>2 XOR 7 = 5</code>&nbsp;。</p>
</div>

<p><strong class="example">示例 2：</strong></p>

<div class="example-block">
<p><span class="example-io"><b>输入：</b>nums = [4,2,5,6,7], k = 2</span></p>

<p><span class="example-io"><b>输出：</b>2</span></p>

<p><strong>解释：</strong></p>

<p>子序列&nbsp;<code>[4, 5, 6, 7]</code>&nbsp;的值最大，为&nbsp;<code>(4 OR 5) XOR (6 OR 7) = 2</code>&nbsp;。</p>
</div>

<p>&nbsp;</p>

<p><strong>提示：</strong></p>

<ul>
	<li><code>2 &lt;= nums.length &lt;= 400</code></li>
	<li><code>1 &lt;= nums[i] &lt; 2<sup>7</sup></code></li>
	<li><code>1 &lt;= k &lt;= nums.length / 2</code></li>
</ul>