This was easy because I have solved it in codezen already. I used 2 pointers head and tail and initially they were NULL. Then I compared the head of 2 given linked lists and one which was smaller will be the new head of my sorted linked lists. Then I applied simple merge function of the merge sort while comparing elements and adding to my linked lists accordingly.

I told him 2 approach. One was based on sorting in nlogn time. He told me to optimize it. I did it in linear time using hashing. He was satisfied with it.

There are 3 ways to solve it. One is use 2 loops i,j from zero to length of the string. Check if string from i to j have unique character or not.

To make concurrency cheaper, the execution aspect of process is separated out into threads. As such, the OS now manages threads and processes

Kernel-Level threads make concurrency much cheaper than process because, much less state to allocate and initialize. However, for fine-grained concurrency, kernel-level threads still suffer from too much overhead.

It depends on the requirment.

Select salary from employee order by desc limit 3,1