Associate Software Engineer

You are given an integer array 'ARR' of size 'N' and an integer 'S'. Your task is to return the list of all pairs of elements such that each sum of elements of each pair equals 'S'.

Note:

Each pair should be sorted i.e the first value should be less than or equals to the second value. 

Return the list of pairs sorted in non-decreasing order of their first value. In case if two pairs have the same first value, the pair with a smaller second value should come first.

You have been given a board where there are '2' rows and 'N' columns. You have an infinite supply of 2x1 tiles, and you can place a tile in the following ways:

1. Horizontally as 1x2 tile
2. Vertically as 2x1 tile

Count the number of ways to tile the given board using the available tiles.

Note :

The number of ways might be large so output your answer modulo 10^9 + 7.

Here an example of tile and board for 'N' = 4 :

My interview started with introduction and then my college life and what do I like to do in my college.
Then they asked me about my internship which I was doing at that time. We discussed about the projects and technologies I learnt and was doing during my internships.
Then they came straight to my college life like how many friends do I have and what kind of relationship do I with them.
They also asked me situational questions like one of them is, "What if I had a fight with someone and now that person is hating and speaking nonsense of you so what will I do"
Then they asked me about my greatest achievement when my parents were proud of me, so I didn't had any recent such big achievement so I told them about one from my senior school they were more than happy to listen that and even congratulated me.
Then they asked me some behavior questions and about some team work and leadership situations.
We discussed about my hobbies and how often I do them.
We discussed about my school projects and some volunteering work I did. 
Overall it was a nice experience. They were very encouraging and that help me boost my confidence.