leetcode-problemset/leetcode-cn/problem (Chinese)/点名 [que-shi-de-shu-zi-lcof].html

<p>某班级 n 位同学的学号为 0 ~ n-1。点名结果记录于升序数组 <code>records</code>。假定仅有一位同学缺席，请返回他的学号。</p>

<p>&nbsp;</p>

<p><strong>示例 1：</strong></p>

<pre>
<strong>输入：</strong>records = [0,1,2,3,5]
<strong>输出：</strong>4
</pre>

<p><strong>示例 2：</strong></p>

<pre>
<strong>输入：</strong>records = [0, 1, 2, 3, 4, 5, 6, 8]
<strong>输出：</strong>7</pre>

<p>&nbsp;</p>

<p><b>提示：</b></p>

<p><code>1 &lt;= records.length&nbsp;&lt;= 10000</code></p>