.NET Developer Written Exam

What they ask

.NET developer hiring starts with a written exam in four sections, then an HR interview.

• SQL: joins, aggregates, and one query you write in full, for example "customers with more than one active line and the total of their last bills".
• Web development: HTTP verbs and status codes, what MVC separates, session vs cookie vs token, and how a form post reaches a controller action.
• Problem solving: two short problems on paper. Reported style: find the value that appears twice in an array of size n + 1 containing values 1..n; reverse the words of a sentence in place.
• .NET framework: CLR and garbage collection basics, value vs reference types, IDisposable and using, async/await, and the difference between IEnumerable and IQueryable.

Solve the first problem-solving item in the starter code below.

Examples

• [1, 3, 4, 2, 2] returns 2.
• [3, 1, 3, 4, 2] returns 3.

Constraints

• 2 <= n <= 10^5, exactly one value repeats.

What they look for

• Clean handwritten code with the edge cases named.
• Solid SQL; this is the section that eliminates most people.
• Short, correct definitions in the .NET section rather than long essays.