Two rounds of phone screening, back to back.

The first interview was challenging. The interviewer was very silent, and the questions seemed difficult for me, especially as this was my first interview ever. I felt very nervous.

The second interview went very well. The interviewer was very helpful and cool.

In both interviews, only two questions were asked, one question in each. I just kept adding and improvising.

First Round:

A represents the set { sum of a list of numbers } 1, 2, 3, 4, 5, 6 ------like this

A = [(2,3), (5,7), (9,10)]

B represents the set { another list of numbers } 1, 2, 3, 4, 5, 6, 7, 8, 9, 0

B = [(1,3), (5,10)]

These lists always have the following properties:

• Intervals are listed in ascending order.
• Intervals are merged whenever possible. i.e. you'll never see [(1,3), (4,5)] because it would be merged into [(1,5)]

1. When we see a new event ID, we need to add it to the set. Write a function to add a number to one of these sets, while maintaining the above properties.

Second Round:

1. Binary search
2. Find the first repeated element in the array.
3. What is the time complexity of the code I wrote?
4. What can you do to improve the time complexity?
5. What is the space complexity for the program I wrote?