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LeetCode SQL 50 Solution/596. Classes More Than 5 Students/596. Classes More Than 5 Students.py

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+import pandas as pd
+
+def classes_with_five_or_more_students(courses: pd.DataFrame) -> pd.DataFrame:
+    # Group by 'class' and count the number of students
+    result = courses.groupby('class').filter(lambda x: len(x) >= 5)
+    # Return only the distinct class names
+    return result[['class']].drop_duplicates().reset_index(drop=True)

LeetCode SQL 50 Solution/596. Classes More Than 5 Students/readme.md

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+# **596. Classes More Than 5 Students**
+
+## **Problem Statement**
+You are given a table `Courses` that contains the names of students and the class in which they are enrolled.
+
+### **Courses Table**
+```
++---------+---------+
+| Column  | Type    |
++---------+---------+
+| student | varchar |
+| class   | varchar |
++---------+---------+
+```
+- The combination of `(student, class)` is the **primary key**.
+- Each row indicates the name of a student and the class they are enrolled in.
+
+### **Task:**
+Write a solution to find all the classes that have **at least five students**.
+
+Return the result table in **any order**.
+
+---
+
+## **Example 1:**
+
+### **Input:**
+```
+Courses table:
++---------+----------+
+| student | class    |
++---------+----------+
+| A       | Math     |
+| B       | English  |
+| C       | Math     |
+| D       | Biology  |
+| E       | Math     |
+| F       | Computer |
+| G       | Math     |
+| H       | Math     |
+| I       | Math     |
++---------+----------+
+```
+
+### **Output:**
+```
++---------+
+| class   |
++---------+
+| Math    |
++---------+
+```
+
+### **Explanation:**
+- **Math** has 6 students, so it is included.
+- **English**, **Biology**, and **Computer** have fewer than 5 students, so they are excluded.
+
+---
+
+## **Solution Approaches**
+
+### **SQL Solution**
+```sql
+SELECT class
+FROM Courses
+GROUP BY class
+HAVING COUNT(student) >= 5;
+```
+**Explanation:**
+- The query groups records by `class`.
+- The `HAVING` clause filters out groups with fewer than 5 students.
+
+---
+
+### **Pandas Solution**
+```python
+import pandas as pd
+
+def classes_with_five_or_more_students(courses: pd.DataFrame) -> pd.DataFrame:
+    # Group by 'class' and count the number of students
+    result = courses.groupby('class').filter(lambda x: len(x) >= 5)
+    # Return only the distinct class names
+    return result[['class']].drop_duplicates().reset_index(drop=True)
+
+# Example usage:
+# courses_df = pd.read_csv('courses.csv')
+# print(classes_with_five_or_more_students(courses_df))
+```
+**Explanation:**
+- The Pandas solution groups the DataFrame by `class` and filters groups with 5 or more students.
+- It then extracts and returns the distinct class names.
+
+---
+
+## **File Structure**
+```
+LeetCode596/
+├── problem_statement.md       # Contains the problem description and constraints.
+├── sql_solution.sql           # Contains the SQL solution.
+├── pandas_solution.py         # Contains the Pandas solution for Python users.
+├── README.md                  # Overview of the problem and available solutions.
+```
+
+---
+
+## **Useful Links**
+- [LeetCode Problem 596](https://leetcode.com/problems/classes-more-than-5-students/)
+- [SQL GROUP BY and HAVING Clause](https://www.w3schools.com/sql/sql_groupby.asp)
+- [Pandas GroupBy Documentation](https://pandas.pydata.org/docs/reference/api/pandas.DataFrame.groupby.html)
+