Senior Systems Engineer

You are given a paragraph that may have letters both in lowercase and uppercase, spaces, and punctuation. You have also given a list of banned words. Now your task is to find the most frequent word which is not in the list of banned words. There will always be a solution, and the solution will be unique.

While comparing words, you can ignore whether the letter is lowercase or uppercase. For example, ‘AsK’ and ‘aSK’ are the same. The words will always contain only alphabets or we can say words will be separated by spaces or punctuation. The answer will be in uppercase letters.

The words in the banned list will always be in upper letters and free from punctuation and spaces.

For example :

Paragraph = ‘It's a square SqUare. It's a FLAT flat.’ 
Banned =[FLAT, IT, S]. 
So we can see these words [IT, S, SQUARE, FLAT ]  are most frequent.
Now we will look at to banned list and we can see 3 of the words are banned.
So we have a unique answer SQUARE which has a frequency of 2 and not on the banned list.

You are given an integer ‘N’, your task is to find and return the N’th Fibonacci number using matrix exponentiation.

Since the answer can be very large, return the answer modulo 10^9 +7.

Fibonacci number is calculated using the following formula:

F(n) = F(n-1) + F(n-2), 
Where, F(1) = F(2) = 1.

For Example:

For ‘N’ = 5, the output will be 5.

Design a payment gateway architecture.

• Tell me about yourself
• What are your strengths and weakness?
• What according to you should be one's approach to overcome his weakness?
• What are your salary expectations?