Boomerang Interview Experience | Set 1 (For SDE position)

Round 1:

Writing code for the below questions in 45 mins(standard same question in boomerang)
1. Given a boolean matrix A. Modify the matrix such that if A[i,j]=1 make ith row & jth column as 1.
2. Code to check if a tree is BST or not
3. Write a program to find number of words in a file not using any standard tokenizing API’s.

Round 2:
1. Stream of numbers are flowing in and given a window of size w. Give the minimum number of the current window. Optimize to get answer in O(n) time if n is so far size of input stream.

2. Given n, you will be getting stream of sets each set may contain like (1,3,4,5) which signifies that 1,3,4,5 are related. Similarly you may get like (6,7) , (1,8).
And you will be asked to find whether 1 & 4 are related => Yes (as they are from same set).
3 & 8 are related => yes as 8 & 3 are related through 1.
5 & 7 are related =>No

Round 3:
1. Design question on DB for maintaining e-commerce various cat,sub cat,sub sub cat
2. Given various bus schedule arrival and departure (Ai,Di). Find the minimum number of platforms needed at any point of time.

Round 4 (Machine Round) (standard same question in boomerang)
You will be given access to a test machine in aws. You are asked to setup below
1. Install erlang
2. Use any web framework to expose an URL to outside world to print Hello World
3. Use any DB of ur choice and store a sample string X
4. Expose another URL which when accessed on a browser shows “Hello world $X”