leetcode-problemset/leetcode-cn/problem (English)/在既定时间做作业的学生人数(English) [number-of-students-doing-homework-at-a-given-time].html

<p>Given two integer arrays <code>startTime</code> and <code>endTime</code> and given an integer <code>queryTime</code>.</p>

<p>The <code>ith</code> student started doing their homework at the time <code>startTime[i]</code> and finished it at time <code>endTime[i]</code>.</p>

<p>Return <em>the number of students</em> doing their homework at time <code>queryTime</code>. More formally, return the number of students where <code>queryTime</code> lays in the interval <code>[startTime[i], endTime[i]]</code> inclusive.</p>

<p>&nbsp;</p>
<p><strong>Example 1:</strong></p>

<pre>
<strong>Input:</strong> startTime = [1,2,3], endTime = [3,2,7], queryTime = 4
<strong>Output:</strong> 1
<strong>Explanation:</strong> We have 3 students where:
The first student started doing homework at time 1 and finished at time 3 and wasn&#39;t doing anything at time 4.
The second student started doing homework at time 2 and finished at time 2 and also wasn&#39;t doing anything at time 4.
The third student started doing homework at time 3 and finished at time 7 and was the only student doing homework at time 4.
</pre>

<p><strong>Example 2:</strong></p>

<pre>
<strong>Input:</strong> startTime = [4], endTime = [4], queryTime = 4
<strong>Output:</strong> 1
<strong>Explanation:</strong> The only student was doing their homework at the queryTime.
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>startTime.length == endTime.length</code></li>
	<li><code>1 &lt;= startTime.length &lt;= 100</code></li>
	<li><code>1 &lt;= startTime[i] &lt;= endTime[i] &lt;= 1000</code></li>
	<li><code>1 &lt;= queryTime &lt;= 1000</code></li>
</ul>