SDE - 1

Preeti has decided to go to the Grand Mall to buy some stuff for her father’s birthday. On reaching the place, she found a fascinating shop that has an unlimited quantity of each item they sell. The shop has N different types of items. However, here Preeti has a fixed budget and can buy a maximum of K items. She can buy any amount of items ≥ 1 and ≤ K.

She can buy an arbitrary quantity of each item. There is no restriction on different items having different quantities. Now, Preeti wonders the number of different ways in which she can shop today. Two ways are considered different if the quantity of at least 1 of the items purchased is different. Preeti finds this task too hard to complete and requires your help. Your task is to find the required answer.

Note:

As the answer can be large, return your answer modulo 10^9  + 7.

Follow Up:

Can you solve this using constant extra space?

It was a Technical round. The level was medium.
Technical Questions-
1. What is Multi-Threading? (Learn)
2. Give differences between Java and C++. (Learn)
3. OOPs Concepts. (Learn)
4. Some basic SQL Queries. 
5. Why is Java more secure? What is JVM? (Learn)
 

1. Which is your dream company? 
2. Are you ready for relocation?
3. Why do you want Barclays? 
4. Where do you expect yourself after 5 years? 
5. What do you know about Barclays? 
The interviewer was a lady and she was good and helpful.