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Intro, then straight to 2 sql and 2 python questions, followed by questions on data engineering related to:

• data modeling
• about past company project
• normalization
• fact dim
• scd
• how to create historical db

I have a table with follower and followee (where the follower follows the followee), how do I return a table of mutual follows?

How can we transpose a table using SQL (changing rows to column or vice-versa)?

Given an integer array nums, find the contiguous subarray (containing at least one number) which has the largest sum and return its sum.

Example:

• Input: [-2,1,-3,4,-1,2,1,-5,4]
• Output: 6
• Explanation: [4,-1,2,1] has the largest sum = 6

Given a list of integers, return indices of the two numbers such that they add up to a specific target. You may assume that each input would have exactly one solution, and you may not use the same element twice.

Example:

• Input: nums = [2,7,11,15], target = 9
• Output: [0,1]
• Explanation: Because nums[0] + nums[1] == 9, we return [0, 1].

Questions on data engineer, about past company project, normalization, SCD, data modeling questions.