C# Algorithms and SQL Online Test
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The C# Algorithms and SQL online test assesses candidates' knowledge of SQL queries and evaluates their algorithmic-thinking skills using C#.
It's an ideal test for pre-employment screening. A good developer should be able to work closely with the database layer and solve back-end problems where any improvement to computational complexity would produce a significantly more efficient solution.
This online test requires candidates to design and analyze algorithms using C# and to write SQL queries that extract, combine, and manipulate data.
Recommended Job Roles
.NET Developer
Back-End Developer
C# Developer
SQL Developer
Web Developer
Sample Candidate Report
Sample Free Questions
Students
3min
-
Easy
Easy
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CODE
SQL
Aggregation
Public
SQL
SQL is the dominant technology for accessing application data. It is increasingly becoming a performance bottleneck when it comes to scalability. Given its dominance, SQL is a crucial skill for all engineers.
Aggregation
An aggregate function is typically used in database queries to group together multiple rows to form a single value of meaningful data. A good programmer should be skilled at using data aggregation functions when interacting with databases.
Public
Public questions (free account) are common interview questions. They are great for practicing, or if you want to filter candidates using the classic problems.
Given the following data definition, write a query that returns the number of students whose first name is John. String comparisons should be case sensitive.
TABLE students id INTEGER PRIMARY KEY, firstName VARCHAR(30) NOT NULL, lastName VARCHAR(30) NOT NULL
Enrollment
5min
-
Easy
Easy
-
CODE
SQL
Conditions
Update
Public
SQL
SQL is the dominant technology for accessing application data. It is increasingly becoming a performance bottleneck when it comes to scalability. Given its dominance, SQL is a crucial skill for all engineers.
Conditions
Conditional statements are a feature of most programming and query languages. They allow the programmer to control what computations are carried out based on a Boolean condition.
Update
The UPDATE statement is used to modify the existing records in a table and is one of the most used operations for working with the database.
Public
Public questions (free account) are common interview questions. They are great for practicing, or if you want to filter candidates using the classic problems.
A table containing the students enrolled in a yearly course has incorrect data in records with ids between 20 and 100 (inclusive).
TABLE enrollments id INTEGER NOT NULL PRIMARY KEY year INTEGER NOT NULL studentId INTEGER NOT NULL
Write a query that updates the field 'year' of every faulty record to 2015.
Binary Search Tree
15min
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Easy
Easy
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CODE
C#
Algorithmic thinking
Data structures
Public
C#
The C# programming language is a simple, modern, general-purpose, object-oriented programming language. Having a basic familiarity with the programming language used on the job is a prerequisite for quickly getting up to speed.
Algorithmic thinking
When designing and/or analyzing an algorithm or data structure, it is important to consider the performance and structure of an implementation. Algorithmic thinking is one of the key traits of a good programmer, especially one working on complex or performance-critical code.
Data structures
Choosing the right data structure to solve a problem can have huge implications on the performance of an application. Knowing when to use a specific data structure is one of the most important skills for a programmer.
Public
Public questions (free account) are common interview questions. They are great for practicing, or if you want to filter candidates using the classic problems.
Binary search tree (BST) is a binary tree where the value of each node is larger or equal to the values in all the nodes in that node's left subtree and is smaller than the values in all the nodes in that node's right subtree.
Write a function that, efficiently with respect to time used, checks if a given binary search tree contains a given value.
For example, for the following tree:
- n1 (Value: 1, Left: null, Right: null)
- n2 (Value: 2, Left: n1, Right: n3)
- n3 (Value: 3, Left: null, Right: null)
Call to Contains(n2, 3) should return true since a tree with root at n2 contains number 3.
Premium Questions
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Questions
Prefix, Bicycle, Classroom, Runner, Movies, Disposable Wrapper, Index Performance, Poll, Rectangles, Read Write Execute, Needle, Log Parser, Driver Exam, Vectors, Crop Ratio, Retirees, Chicken, Racer, Authors, Countries, Employee Manager, Merge Stock Index, Paragraph, Username, Chain Link, Hobbies, Sort Params, Node, Cheapest Product, Programmer Teacher, Movies Live, Read First Line, Stack to List, ATM Locations, Department Report, Developers, Delete Orders, Product Refactoring, Restaurant Menu, Roads, Sales, Snapshot, Student Activities, Transactions, Projects, Date Transform, Document Store, Youngest Child, SMS Messages, Procedural Generator, Document Counter, Adder, Shelf, Internal Nodes, Window Manager, Moving Total, Entry, Unique Numbers, Rare, Paper Strip, Max Sum, Friend, Remove Repetitions, Unique Name, Log Patch, Stories, Train, Platformer, Shipping, Segment, Eye of the Storm, Chinese Box, Tasks, Weighted Average, Ingredients, Autocomplete, Bank Branches, Hospital Patients, Menu Items, Ban Users, Shining Star, Unloading TrucksSkills
C#C#
The C# programming language is a simple, modern, general-purpose, object-oriented programming language. Having a basic familiarity with the programming language used on the job is a prerequisite for quickly getting up to speed.
LINQ
LINQ provides a compile functional interface for querying datasets. A good .NET developer should be able to take full advantage of this.
Language
A programmer should use a language as a tool, always taking advantage of language-specific data types and built-in functions.
Bug fixing
Everyone makes mistakes. A good programmer should be able to find and fix a bug in their or someone else's code.
Memory management
Memory management allows programs to request memory dynamically from the operating system, and free it for reuse when no longer needed. Many modern programming languages automate this process; however, it should still be an important consideration when implementing an application.
SQL
SQL is the dominant technology for accessing application data. It is increasingly becoming a performance bottleneck when it comes to scalability. Given its dominance, SQL is a crucial skill for all engineers.
Aggregation
An aggregate function is typically used in database queries to group together multiple rows to form a single value of meaningful data. A good programmer should be skilled at using data aggregation functions when interacting with databases.
Subqueries
Subqueries are commonly used in database interactions, making it important for a programmer to be skilled at writing them.
OOP
Object-oriented programming is a paradigm based on encapsulating logic and data into objects, which may then contain fields and procedures. Many of the most widely used programming languages are based on OOP, making it a very important concept in modern programming.
Indexes
The proper implementation and use of indexes are important for improving the performance of database queries.
Conditions
Conditional statements are a feature of most programming and query languages. They allow the programmer to control what computations are carried out based on a Boolean condition.
Arithmetic
Arithmetic is a fundamental branch of mathematics. An understanding of arithmetic concepts, and their application, is important for every candidate.
Strings
The string data structure is used to represent text. It is one of the most commonly used data structures. Therefore, every programmer should be skilled at string manipulation.
Stream
A stream is a sequence of data elements made available over time. It is particularly useful for tasks that may benefit from being asynchronous, including tasks such as I/O processing or reading from a file, and as such is important for developers to understand.
Serialization
Familiarity with data serialization to and from formats such as XML and JSON is important as it is commonly used for interprocess communication
Exceptions
Exceptions exist in most modern programming languages, making it important for a programmer to understand them and know how to handle them.
Searching
Every programmer should be familiar with data-searching methods, as they are very common in data-analysis processes.
Insertion
Even though most database insert queries are simple, a good programmer should know how to handle more complicated situations like batch inserts.
Multithreading
Multi-threading allows a process to make more efficient use of modern hardware by allowing code to execute asynchronously. It can drastically improve the performance of any app; however, it can be tricky to get right, making this an important topic for any programmer.
Joins
A normalized database is normally made up of multiple tables. Joins are, therefore, required to query across multiple tables.
Union
In mathematics, a union typically involves testing if an element exists in two or more sets. This definition also applies as an operator and function in various programming languages. As one of the most common collection operations, alongside intersection, it's an important topic for any candidate to understand.
Data structures
Choosing the right data structure to solve a problem can have huge implications on the performance of an application. Knowing when to use a specific data structure is one of the most important skills for a programmer.
Arrays
An array is a container of a fixed number of objects of a similar type. It is a fundamental component of most programming languages.
Iteration
Iteration is the act of repeating a process, or cycling through a collection. Iteration is one of the fundamental flow control tools available to developers.
Algorithmic thinking
When designing and/or analyzing an algorithm or data structure, it is important to consider the performance and structure of an implementation. Algorithmic thinking is one of the key traits of a good programmer, especially one working on complex or performance-critical code.
Constraints
Constraints are used to define rules and relationships. They are applied to a dataset. A constraint may take many forms, such as x ≤ 5 in a programming language and a NOT NULL constraint in a SQL table definition.
Database Schema
A database schema defines how data is stored in a database. An SQL database uses a schema to define tables consisting of rows and columns that use fixed data types to store data. Formalizing how data is stored is the first step towards building an application or service.
Delete
The delete statement is used to delete records in a table and is one of the four basic CRUD functions (create, read, update, and delete) required for working with any persistent storage.
Refactoring
The process of restructuring existing computer code without changing its external behavior. It is essential for keeping code readable and maintainable.
Update
The UPDATE statement is used to modify the existing records in a table and is one of the most used operations for working with the database.
Views
A database view is a result set that is defined by a stored query, the results of which can can also be queried. As a fundamental and widely used database construct, it's useful for candidates to understand how and when they should be used.
Random
Random number generators are used to generate random numbers and/or symbols. There are a wide variety of random number generators each with very specific use cases, as such it's important for all developers to know and understand when to use each type.
Test case design
Being able to create a set of test cases that ensure adequate test coverage is a key skill for creating a successful test. It is desirable for the test suite also to be optimal, i.e. to minimize test execution effort and time without affecting the test coverage.
Graphs
Many real-life situations are best modeled by graphs. Therefore, an in-depth knowledge of graph data structures is important for a good programmer.
Extension Methods
Extension methods enable are method of extending existing types without extending the type, recompiling or modifying the original type. They are a useful feature of developers who want to write and maintain clean and concise code.
Dynamic programming
Dynamic programming methods for code optimization can be very useful to a programmer who understands them.
Performance tuning
The performance of an application or system is important. The responsiveness and scalability of an application are all related to how performant an application is. Each algorithm and query can have a large positive or negative effect on the whole system.
TDD
Test-driven development (TDD) is a software development process that relies on the repetition of a very short development cycle: requirements are turned into very specific test cases, based on which the software is improved only in order to pass the new tests. TDD is an essential skill for modern programmers.
Sorting
Every programmer should be familiar with data-sorting methods, as sorting is very common in data-analysis processes.
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