leetcode-problemset/leetcode-cn/problem (Chinese)/子数组按位与值为 K 的数目 [number-of-subarrays-with-and-value-of-k].html

<p>给你一个整数数组&nbsp;<code>nums</code>&nbsp;和一个整数&nbsp;<code>k</code>&nbsp;，请你返回&nbsp;<code>nums</code>&nbsp;中有多少个<span data-keyword="subarray-nonempty">子数组</span>满足：子数组中所有元素按位&nbsp;<code>AND</code>&nbsp;的结果为 <code>k</code>&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 = [1,1,1], k = 1</span></p>

<p><span class="example-io"><b>输出：</b>6</span></p>

<p><strong>解释：</strong></p>

<p>所有子数组都只含有元素 1 。</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 = [1,1,2], k = 1</span></p>

<p><span class="example-io"><b>输出：</b>3</span></p>

<p><b>解释：</b></p>

<p>按位&nbsp;<code>AND</code>&nbsp;值为 1 的子数组包括：<code>[<u><strong>1</strong></u>,1,2]</code>, <code>[1,<u><strong>1</strong></u>,2]</code>, <code>[<u><strong>1,1</strong></u>,2]</code>&nbsp;。</p>
</div>

<p><strong class="example">示例 3：</strong></p>

<div class="example-block">
<p><span class="example-io"><b>输入：</b>nums = [1,2,3], k = 2</span></p>

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

<p><strong>解释：</strong></p>

<p>按位&nbsp;<code>AND</code>&nbsp;值为 2 的子数组包括：<code>[1,<b><u>2</u></b>,3]</code>, <code>[1,<u><strong>2,3</strong></u>]</code>&nbsp;。</p>
</div>

<p>&nbsp;</p>

<p><strong>提示：</strong></p>

<ul>
	<li><code>1 &lt;= nums.length &lt;= 10<sup>5</sup></code></li>
	<li><code>0 &lt;= nums[i], k &lt;= 10<sup>9</sup></code></li>
</ul>