mirror of
https://gitee.com/coder-xiaomo/leetcode-problemset
synced 2025-09-04 06:51:41 +08:00
140 lines
6.1 KiB
HTML
140 lines
6.1 KiB
HTML
<p>表：<code>students</code></p>
|
||
|
||
<pre>
|
||
+--------------+---------+
|
||
| Column Name | Type |
|
||
+--------------+---------+
|
||
| student_id | int |
|
||
| student_name | varchar |
|
||
| major | varchar |
|
||
+--------------+---------+
|
||
student_id 是这张表的唯一主键。
|
||
每一行包含有关学生及其学术专业的信息。
|
||
</pre>
|
||
|
||
<p>表：<code>study_sessions</code></p>
|
||
|
||
<pre>
|
||
+---------------+---------+
|
||
| Column Name | Type |
|
||
+---------------+---------+
|
||
| session_id | int |
|
||
| student_id | int |
|
||
| subject | varchar |
|
||
| session_date | date |
|
||
| hours_studied | decimal |
|
||
+---------------+---------+
|
||
session_id 是这张表的唯一主键。
|
||
每一行代表一个学生针对特定学科的学习时段。
|
||
</pre>
|
||
|
||
<p>编写一个解决方案来找出遵循 <strong>螺旋学习模式</strong> 的学生——即那些持续学习多个学科并按循环周期进行学习的学生。</p>
|
||
|
||
<ul>
|
||
<li>螺旋学习模式意味着学生以重复的顺序学习至少 <code>3</code> 个 <strong>不同的学科</strong>。</li>
|
||
<li>模式必须重复 <strong>至少</strong><strong> </strong><code>2</code><strong> 个完整周期</strong>（最少 <code>6</code> 次学习记录）。</li>
|
||
<li>两次学习记录必须是间隔不超过 <code>2</code> 天的 <strong>连续日期</strong>。</li>
|
||
<li>计算 <strong>循环长度</strong>（模式中不同的学科数量）。</li>
|
||
<li>计算模式中所有学习记录的 <strong>总学习时长</strong>。</li>
|
||
<li>仅包含循环长度 <strong>至少为 </strong><strong> </strong><code>3</code><strong> 门学科</strong> 的学生。</li>
|
||
</ul>
|
||
|
||
<p>返回结果表按循环长度 <strong>降序</strong> 排序，然后按总学习时间 <strong>降序</strong> 排序。</p>
|
||
|
||
<p>结果格式如下所示。</p>
|
||
|
||
<p> </p>
|
||
|
||
<p><strong class="example">示例：</strong></p>
|
||
|
||
<div class="example-block">
|
||
<p><strong>输入：</strong></p>
|
||
|
||
<p>students 表：</p>
|
||
|
||
<pre class="example-io">
|
||
+------------+--------------+------------------+
|
||
| student_id | student_name | major |
|
||
+------------+--------------+------------------+
|
||
| 1 | Alice Chen | Computer Science |
|
||
| 2 | Bob Johnson | Mathematics |
|
||
| 3 | Carol Davis | Physics |
|
||
| 4 | David Wilson | Chemistry |
|
||
| 5 | Emma Brown | Biology |
|
||
+------------+--------------+------------------+
|
||
</pre>
|
||
|
||
<p>study_sessions 表：</p>
|
||
|
||
<pre class="example-io">
|
||
+------------+------------+------------+--------------+---------------+
|
||
| session_id | student_id | subject | session_date | hours_studied |
|
||
+------------+------------+------------+--------------+---------------+
|
||
| 1 | 1 | Math | 2023-10-01 | 2.5 |
|
||
| 2 | 1 | Physics | 2023-10-02 | 3.0 |
|
||
| 3 | 1 | Chemistry | 2023-10-03 | 2.0 |
|
||
| 4 | 1 | Math | 2023-10-04 | 2.5 |
|
||
| 5 | 1 | Physics | 2023-10-05 | 3.0 |
|
||
| 6 | 1 | Chemistry | 2023-10-06 | 2.0 |
|
||
| 7 | 2 | Algebra | 2023-10-01 | 4.0 |
|
||
| 8 | 2 | Calculus | 2023-10-02 | 3.5 |
|
||
| 9 | 2 | Statistics | 2023-10-03 | 2.5 |
|
||
| 10 | 2 | Geometry | 2023-10-04 | 3.0 |
|
||
| 11 | 2 | Algebra | 2023-10-05 | 4.0 |
|
||
| 12 | 2 | Calculus | 2023-10-06 | 3.5 |
|
||
| 13 | 2 | Statistics | 2023-10-07 | 2.5 |
|
||
| 14 | 2 | Geometry | 2023-10-08 | 3.0 |
|
||
| 15 | 3 | Biology | 2023-10-01 | 2.0 |
|
||
| 16 | 3 | Chemistry | 2023-10-02 | 2.5 |
|
||
| 17 | 3 | Biology | 2023-10-03 | 2.0 |
|
||
| 18 | 3 | Chemistry | 2023-10-04 | 2.5 |
|
||
| 19 | 4 | Organic | 2023-10-01 | 3.0 |
|
||
| 20 | 4 | Physical | 2023-10-05 | 2.5 |
|
||
+------------+------------+------------+--------------+---------------+
|
||
</pre>
|
||
|
||
<p><strong>输出：</strong></p>
|
||
|
||
<pre class="example-io">
|
||
+------------+--------------+------------------+--------------+-------------------+
|
||
| student_id | student_name | major | cycle_length | total_study_hours |
|
||
+------------+--------------+------------------+--------------+-------------------+
|
||
| 2 | Bob Johnson | Mathematics | 4 | 26.0 |
|
||
| 1 | Alice Chen | Computer Science | 3 | 15.0 |
|
||
+------------+--------------+------------------+--------------+-------------------+
|
||
</pre>
|
||
|
||
<p><strong>解释：</strong></p>
|
||
|
||
<ul>
|
||
<li><strong>Alice Chen (student_id = 1):</strong>
|
||
|
||
<ul>
|
||
<li>学习序列：Math → Physics → Chemistry → Math → Physics → Chemistry</li>
|
||
<li>模式：3 门学科（Math，Physics，Chemistry）重复 2 个完整周期</li>
|
||
<li>连续日期：十月 1-6，没有超过 2 天的间隔</li>
|
||
<li>循环长度：3 门学科</li>
|
||
<li>总时间：2.5 + 3.0 + 2.0 + 2.5 + 3.0 + 2.0 = 15.0 小时</li>
|
||
</ul>
|
||
</li>
|
||
<li><strong>Bob Johnson (student_id = 2):</strong>
|
||
<ul>
|
||
<li>学习序列：Algebra → Calculus → Statistics → Geometry → Algebra → Calculus → Statistics → Geometry</li>
|
||
<li>模式：4 门学科（Algebra，Calculus，Statistics，Geometry）重复 2 个完整周期</li>
|
||
<li>连续日期：十月 1-8，没有超过 2 天的间隔</li>
|
||
<li>循环长度：4 门学科</li>
|
||
<li>总时间：4.0 + 3.5 + 2.5 + 3.0 + 4.0 + 3.5 + 2.5 + 3.0 = 26.0 小时</li>
|
||
</ul>
|
||
</li>
|
||
<li><strong>未包含学生：</strong>
|
||
<ul>
|
||
<li>Carol Davis (student_id = 3)：仅 2 门学科（生物，化学）- 未满足至少 3 门学科的要求</li>
|
||
<li>David Wilson (student_id = 4)：仅 2 次学习课程，间隔 4 天 - 不符合连续日期要求</li>
|
||
<li>Emma Brown (student_id = 5)：没有记录学习课程</li>
|
||
</ul>
|
||
</li>
|
||
</ul>
|
||
|
||
<p>结果表以 cycle_length 降序排序，然后以 total_study_hours 降序排序。</p>
|
||
</div>
|