Skip to main content

Interview Questions for experienced professionals: Part 1


This article is for those who are prepaing for any technical job interview. Different organisation have different interview process and here I am sharing the interview of one of the consulting firms.

Interview was categorised into multiple sections to understand T shaped skills. T shaped skills accesses a candidate on core expertise(depth of understanding) and other technical skills(breadth of concepts).  I have catagorised the interview into sections which includes, Algorithms, SQL Server, Innovative Ideas, Technical Knowledge and so on.

You may check your knowledge as well. Try it once.


Algorithms

Q: How to swap the values of two integers with using additional memory? 

Ans: 

public static void SwapInt()
{
int a = 25;
int b = 35;
a = a + b;
b = a - b;
a = a - b;
Console.WriteLine("a=> " + a + " b=> " + b);
}


Q: How to find duplicate in an array? Please not there is only one duplicate value.

Ans: 

Alternative 1

public static void DuplicateInt()
{
int[] intarr = {1, 2, 3, 4, 2, 5, 6};
for(int i=0 ;i<intarr.Length-1;i++)
{
for(int j=intarr.Length-1;j>i;j--)
{
if(intarr[i]==intarr[j])
{
Console.WriteLine("Duplicate is " + intarr[i]);
break;
}
}
}
}


Alternative 2

public static void DuplicateInt()
{
int[] intarr = {1, 2, 3, 4, 2, 5, 5};
Array.Sort(intarr);

for(int i=0 ;i<intarr.Length-1;i++)
{
if(intarr[i]==intarr[i+1])
{
Console.WriteLine("Duplicate is " + intarr[i]);
break;
}
}
}
}


Q: How to reverse the string without using additional memory?

Ans: I could think of this way which is using additional memory. Please share if you have logic which would do the reversal of string without using additional memory.

public static string StringReverse(string str)
{
char[] ca = str.ToCharArray(0,str.Length);
Array.Reverse(ca);
return new string(ca);
}


Q: Push all zero elements in the last of the array.

Ans:

public static void ZeroBack()
{
int[] intarr = {1, 2, 0, 3, 4, 0, 2, 5, 0, 6};
Array.Sort(intarr);
Array.Reverse(intarr);
}


SQL Server

Problem Statement: There are two tables 1. Bank_Account_Customer 2. Customer

Bank_Account_Customer
bank_account_id
account_name
balance_amount


Customer
customer_id
customer_name
bank_account_id

Find all customers who have balance_amount>5000.


Solution:

Select c.customer_name, c.customer_id from Bank_Account_Customer b, Customer c where b.bank_account_id = c.bank_account_id && b.balance_amount > 5000;

The above can be done using Joins as well.


Innovative Ideas

Problem Statement:   Design a vending machine with new approach, keeping Covid in mind.

Solution: We may use Scan code where an user can scan the code of vending machine and make the payment online there itself. As payment will be done, instruction will be sent to vending machine to dispense the item. 


Problem Statement: Design elevator solution with new approach, keeping Covid in mind. 

Solution: We may use voice recognition feature, one can speak on which floor he/she would like to go and that floor number will be highlighted.

There can be N different ways to solve above problems. I have shared what came to my mind that moment of time.


Technical Knowledge

Question: What is difference between Abstract class and Interface and share the scenerios when should we use what?

Answer: 

  • Abstract class can have implementation as well, however Interfaces only have signatures. 
  • Multiple inhertance can't be achieved using Abstract class, however we can inherit multiple interfaces.
  • We can use any access modifier in Abstract class but in interfaces everything is public.

When we have the requirement of a class which contains some common methods and properties whose implementation is different for different classes, we should use abstract class.


Question: What happens when we concatenate string using + sign? What is efficient way to do it?

Answer: String is immutable in .Net which means everytime you use string class method, no matter name is same or different, a new string object is created in memory. More string operations means more memory consumption. 

StringBuilder class provides the way to deal with memory efficiently. If string operations are common in your code, use it. It is not recommended to use when string operations are few.


Next round was on Agile methodology, NFRs(Non functional requirements), DevOps, Root cause analysis approach. Interesting question were asked and discussion was quite impactful. 


Comments

Popular posts from this blog

Cannot alter the login 'sa', because it does not exist or you do not have permission.

Working on projects, it can happen that 'sa' account gets locked. If it is on local machine OR development boxes, onus would be on you to fix it. If scripts and SQL steps are not working, this might help you fixing the issue. Steps to unlock 'sa' account and resetting the password. 1. Open SQL Server Configuration Manager 2. Select SQL Server Services -> 'SQL Server' service. 3. Right click on 'SQL Server' service and click on "Startup Parameters". For 2008, server "Startup Parameters" are inside Advanced tab.   4. Add '-m' in startup parameters as shown above and click on 'Add'. This will put SQL server into 'Single User Mode' and local admin will have 'Super User' rights. For 2008, server you have to add ':-m' in the last of the existing query. 5. Save the settings and Restart the service. 6. Now open the SQL Server Management Studio and connect to database using 'Windows A

Could not load file or assembly 'Microsoft.Web.Infrastructure'

Could not load file or assembly 'Microsoft.Web.Infrastructure, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The system cannot find the file specified. What 'Micorosoft.Web.Infrastructure' does? This dll lets HTTP modules register at run time. Solution to above problem: Copy 'Micorosoft.Web.Infrastructure' dll in bin folder of your project and this problem should be resolved. If you have .Net framework installed on machine, this dll should be present on it. You can search for this dll and copy it in your active project folder.   Alternatively,  you can install this dll using nuget package manager PM> Install-Package Microsoft.Web.Infrastructure -Version 1.0.0 Happy coding!!

Dockerize a dotnet core application with SQL connectivity

Before reading this article, I am assuming that you know Docker, Dotnet core and have a dotnet core application which is trying to connect to SQL server. Read how to build aspnet core app, docker and run the docker container. If docker container is running and you are not able to connect to database, this blog should help you fix it.  Prerequisite -  Make sure code is working via running aspnet core locally via visual studio or command line. Port 1433 is opened for connecting to SQL server. Solution If you have Docker file ready, it should somewhat look like below file -  FROM mcr.microsoft.com/dotnet/core/sdk:3.1 AS build-env WORKDIR /app # Copy csproj and restore as distinct layers COPY /SampleAPI/*.csproj ./ RUN dotnet restore # Copy everything else and build COPY . . WORKDIR /app/SampleAPI RUN dotnet publish -c Production -o publish # Build runtime image FROM mcr.microsoft.com/dotnet/core/aspnet:3.1 WORKDIR /app/SampleAPI COPY --from=build-env /app/SampleAPI . WORK