Koo Interview Experience for SDE1 (1.5 Years Experienced)

Round 1: Questions asked:

• Registration Flow 

  phone number  & OTP -> only way of verification
  Security
  Scalability

  Users (id, name)
  (1, ‘cnn’) , (2, ‘twt’) , (3, ‘yuw’) , (4, ‘uqbd’) 
  updating name 
  batch update name
  (1, ‘wwt’) , (2, ‘bn’), (3, ‘yqa’), (4, ’rck’) 
  q. Batch update query -> 
  update ‘users’ set name = ‘wwt’ where id = 1        
  Users (id, username) - twitter. 
  id - pk - non auto increment -> uuid
  username - unique index non null -> non changeable.

• What is the difference between the primary key and unique index column with the above constraints?

• Given a linked list of size N., The task is to reverse every k node (where k is an input to the function) in the linked list. If the number of nodes is not a multiple of k then left-out nodes, in the end, should be considered as a group and must be reversed

  Input: LinkedList: 1->2->2->4->5->6->7->8->9
  K = 4
  Output: 4 2 2 1 8 7 6 5 9

• Given an array Arr[] of N integers. Find the contiguous sub-array(containing at least one number) which has the maximum sum and return its sum.

  Input:
  N = 5
  Arr[] = {1,2,3,-2,5}
  
  Output: 9
  
  Input:
  N = 6
  Arr[] = {-1,-2,-3,-4}
  
  Output: -1

Verdict: Rejected!