Backend developer intern

Phase 1:
They have started with some javascript questions, like about the event loop, call stack, async await. they were testing my konwledge about javascript. 

Phase 2:
Backend development
I was asked some questions about microservies as I mentioned about a microservies project in my resume. monolith vs microservies, which onc is better.. etc, I was asked about JWT authentication, types of requests in REST architecture, Why graphQL is used.

Phase 3:
DBMS
I was give a SQL query, which was a easy SQL query, I was trying to solve it, but due to lack of practice I didn't do it well, the interviewer helper me. I was asked questions on ACID properties, Indexing, types of indexing, normalization.

You have been given a number of stairs. Initially, you are at the 0th stair, and you need to reach the Nth stair.

Each time, you can climb either one step or two steps.

You are supposed to return the number of distinct ways you can climb from the 0th step to the Nth step.

Note:

Note: Since the number of ways can be very large, return the answer modulo 1000000007.

Example :

N=3

We can climb one step at a time i.e. {(0, 1) ,(1, 2),(2,3)} or we can climb the first two-step and then one step i.e. {(0,2),(1, 3)} or we can climb first one step and then two step i.e. {(0,1), (1,3)}.

You are given an array of integers. You need to sort the array in ascending order using quick sort.

Quick sort is a divide and conquer algorithm in which we choose a pivot point and partition the array into two parts i.e, left and right. The left part contains the numbers smaller than the pivot element and the right part contains the numbers larger than the pivot element. Then we recursively sort the left and right parts of the array.

Example:

Let the array = [ 4, 2, 1, 5, 3 ]
Let pivot to be the rightmost number.

After the 1st level partitioning the array will be { 2, 1, 3, 4, 5 } as 3 was the pivot. After 2nd level partitioning the array will be { 1, 2, 3, 4, 5 } as 1 was the pivot for the left part and 5 was the pivot for the right part. Now our array is sorted and there is no need to divide it again.

Design Google Docs in which multiple people write into the docs simultaneously and be able to share the documents with each other.

Design a Food Delivery system like swiggy