Introduction

In this blog post, we'll share the most commonly asked coding interview questions at Fortinet. If you don't have months to study for your interviews, you can use AI tools like Chatmagic to generate solutions quickly and efficiently - helping you pass the interviews and get the job offer!

Problem #1: Percentage of Users Attended a Contest

Table: Users +-------------+---------+ | Column Name | Type | +-------------+---------+ | user_id | int | | user_name | varchar | +-------------+---------+ user_id is the primary key (column with unique values) for this table. Each row of this table contains the name and the id of a user. Table: Register +-------------+---------+ | Column Name | Type | +-------------+---------+ | contest_id | int | | user_id | int | +-------------+---------+ (contest_id, user_id) is the primary key (combination of columns with unique values) for this table. Each row of this table contains the id of a user and the contest they registered into. Write a solution to find the percentage of the users registered in each contest rounded to two decimals. Return the result table ordered by percentage in descending order. In case of a tie, order it by contest_id in ascending order. The result format is in the following example. Example 1: Input: Users table: +---------+-----------+ | user_id | user_name | +---------+-----------+ | 6 | Alice | | 2 | Bob | | 7 | Alex | +---------+-----------+ Register table: +------------+---------+ | contest_id | user_id | +------------+---------+ | 215 | 6 | | 209 | 2 | | 208 | 2 | | 210 | 6 | | 208 | 6 | | 209 | 7 | | 209 | 6 | | 215 | 7 | | 208 | 7 | | 210 | 2 | | 207 | 2 | | 210 | 7 | +------------+---------+ Output: +------------+------------+ | contest_id | percentage | +------------+------------+ | 208 | 100.0 | | 209 | 100.0 | | 210 | 100.0 | | 215 | 66.67 | | 207 | 33.33 | +------------+------------+ Explanation: All the users registered in contests 208, 209, and 210. The percentage is 100% and we sort them in the answer table by contest_id in ascending order. Alice and Alex registered in contest 215 and the percentage is ((2/3) 100) = 66.67% Bob registered in contest 207 and the percentage is ((1/3) 100) = 33.33%

Topics: Database

Problem #2: Number of Ways to Paint N × 3 Grid

You have a grid of size n x 3 and you want to paint each cell of the grid with exactly one of the three colors: Red, Yellow, or Green while making sure that no two adjacent cells have the same color (i.e., no two cells that share vertical or horizontal sides have the same color). Given n the number of rows of the grid, return the number of ways you can paint this grid. As the answer may grow large, the answer must be computed modulo 109 + 7. Example 1: Input: n = 1 Output: 12 Explanation: There are 12 possible way to paint the grid as shown. Example 2: Input: n = 5000 Output: 30228214 Constraints: n == grid.length 1 <= n <= 5000

Topics: Dynamic Programming