Find Cumulative Salary of an Employee — LeetCode 579 Python Solution

Table: Employee +-------------+------+ | Column Name | Type | +-------------+------+ | id | int | | month | int | | salary | int | +-------------+------+ (id, month) is the primary key (combination of columns with unique values) for this table. Each row in the table indicates the salary of an employee in one month during the year 2020.

+-------------+------+
| Column Name | Type |
+-------------+------+
| id          | int  |
| month       | int  |
| salary      | int  |
+-------------+------+
(id, month) is the primary key (combination of columns with unique values) for this table.
Each row in the table indicates the salary of an employee in one month during the year 2020.

import pandas as pd

def cumulative_salary(employee: pd.DataFrame) -> pd.DataFrame:
    df = employee.sort_values(['id', 'month'])
    df['rolling'] = (
        df.groupby('id')['salary']
          .rolling(3, min_periods=1)
          .sum()
          .reset_index(level=0, drop=True)
    )
    max_month = df.groupby('id')['month'].transform('max')
    res = df[df['month'] < max_month][['id', 'month', 'rolling']]
    res = res.rename(columns={'rolling': 'salary'})
    return res