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Code Problem / Data Structures and Algorithms / Recursion (32)
Code Problem / Data Structures and Algorithms / Binary Search (30)
Code Problem / Data Structures and Algorithms / Linked Lists (26)
Code Problem / Data Structures and Algorithms / Backtracking (26)
Code Problem / Data Structures and Algorithms / Stacks and Queues (25)
Code Problem / Data Structures and Algorithms / Hashing (24)
Databases / SQL / Backup and Recovery (19)
Code Problem / Data Structures and Algorithms / Arrays and Strings (19)
Databases / SQL / Database Normalization (18)
Code Problem / Data Structures and Algorithms / Time Complexity (17)
Databases / SQL / Locking (16)
Databases / SQL / Replication (15)
Databases / SQL / SQL Queries (13)
Code Problem / Data Structures and Algorithms / Graphs (13)
Databases / SQL / Database Security (13)
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Data structures / Arrays
Python
None
About this solution: The candidate's solution is correct. They have correctly identified that the output will be 5. They have also correctly identified the reason for this, which is that the for loop will only iterate through the list once and remove the first 2.
This technical problem involves writing an SQL query that returns the top 3 most purchased products by customers. The example input and output are provided.
About this solution: The solution above is optimal because it uses the ORDER BY and LIMIT clauses to sort the table by product_id in descending order and then limit the results to the top 3.
This problem asks for a SQL query to find all users in a table who have a valid email address.
About this solution: The solution correctly uses the LIKE operator to check if the email contains an @ symbol.
This problem asks for a machine learning model that can predict whether or not a loan will default.
About this solution: This is a good start, but the candidate's solution is incomplete. In order to make an accurate prediction, the machine learning algorithm would need to take into account a variety of factors, such as the borrower's credit score, employment history, and the amount of the loan.
Databases / SQL
SQL
Given a list of customer names and their purchase amounts, this SQL query will find the total amount spent by each customer.
About this solution: The solution provided is correct and demonstrates a good understanding of SQL. The approach is clear and concise.
Machine Learning / Data Science
DifficultyMedium
A machine learning algorithm is used to identify which features in a dataset are most predictive of the target variable. This can be used to reduce the dimensionality of the data and improve the performance of the machine learning models.
About this solution: The candidate's solution is complete and solves the problem. The candidate has correctly identified that a feature selection algorithm is needed to identify the most predictive features. This is a good approach to the problem.
Databases / SQL
SQL
This technical problem deals with creating a function that will take in an array of integers and return the sum of all the even numbers in the array.
About this solution: The candidate's solution correctly calculates the sum of all even numbers in the array. However, the solution could be more concise. For example, the candidate could have used the built-in SUM function to calculate the sum, rather than creating a new table.
Databases / SQL
SQL
Write a SQL query to find the products with the highest price from a given table.
About this solution: The candidate's solution is correct and solves the problem. The approach is straightforward and easy to understand.