6 rounds of technical interview:

1st Round:

• Remove duplicates in an unsorted linked list. Discussed projects, etc.

2nd Round:

• Print the matrix helically.
• Implement the circular queue using an array.

3rd Round:

• Find whether there exists a path in a binary tree whose sum is equal to a given number.
• Optimize it if you know that elements in the tree are all positive.
• Test the elevator.

4th Round:

• Given a binary tree, find the maximum balanced binary subtree.

5th Round:

• If from 0 to 9, each digit represents a set of characters, like: 0 - {a,b,c} 1 - {d,e,f} ... ... with a total of 30 characters. Write a program for a given number (e.g., 945690123) to print all possible strings that can be formed by replacing digits with characters from the above sets.
• Given the coordinates of buildings as (Si, Ei, Hi), representing the start, end, and height of a building. Write a program to print the set of (Xi, Hi) coordinates to draw the skyline of the buildings.

6th Round:

• How would you design in Windows to add an extra attribute to files and design it in such a way that searching for a file based on that attribute is efficient?

I thought I had done the interview fairly well, but I did not get the offer.

The last question stated in the above questions is somewhat difficult.