Paytm Interview – Software Engineer

Hello guys, I am having a 1.3 year of experience and I applied in Paytm money for software engineer profile.

Round 1: online test.

Round 2: all algorithm questions.

Round 3: algorithm + java + spring boot framework.

Round 4: projects + 1 algorithm + query optimization.

Online test(1 hrs):-

   1. Coin change problem modified version, time O(n*n).

   2. Balanced parenthesis problem, and print longest braces length, time O(n).

Algorithm:-

1. Give tree is bst.   O(n) time complexity, space O(1)
2. Maximum sub array without breaking.   O(n) time complexity, space O(1)
3. Lca of a binary tree.  O(n) time complexity, space O(1)
   GeeksforGeeks Link
4. The distance between 2 nodes in tree. O(n) time complexity, space O(1)
   GeeksforGeeks Link
5. Find minkey in stack O(1) time complexity, space O(1)*.
6. array contains 0, 1, 2 sort in O(n) time and O(1) space, in-place sorting.
   GeeksforGeeks Link
7. Find second highest element In array of integer with code optimization.
   GeeksforGeeks Link

Java:-

   1. Internal implementation of HashMap.

   2. Difference b/w Abstract and interface. GeeksforGeeks Link

   3. write a custom class to achieve Mutability.

   4. Java multithreading with both approach differences.

Spring boot:-

   1. Dependencies of injection, inversion of control.

   2. Some annotations.

   3. What’s the problem we are facing without Dependencies of injection.

Project:-

   1. Ask current working project with some internal and deeper discussion.

   2. Query optimization and some internal working of the database which I was using in my current project.

Optimize the query:-

Select a, b, c from table where d=* and e=*;