Machine learning intern

How do you deal with unbalanced data
How SVM hyperplane works
Roles of Generator in GANs etc.

Why Normalization should be done and when to not
When to use SQL and NoSQL type databases

Describe how will you design a recommendation and search engine using ML system design

You are given an integer grid of size ‘N’x’M’, and the cell of the grid contains either of the three values:

0 - An empty cell.

1 - A fresh orange.

2 - A rotten orange.

Every minute, any fresh orange adjacent(4-directionally) to a rotten orange becomes rotten.

You must return the minimum time after which no fresh oranges are left. Return -1 if it's impossible to rot all the fresh oranges.

Example:

Input: [[2,1,1],[1,1,0],[0,0,0]]

Output: 2

At T=0, only orange at (0,0) is rotten.
At T=1, oranges at (0,0),(0,1) and (1,0) are rotten.
At T=2, oranges at (0,0),(0,1),(1,0),(0,2) and (1,1) are rotten. 
No fresh oranges are left after T=2.

Aahad and Harshit always have fun by solving problems. Harshit took a sorted array consisting of distinct integers and rotated it clockwise by an unknown amount. For example, he took a sorted array = [1, 2, 3, 4, 5] and if he rotates it by 2, then the array becomes: [4, 5, 1, 2, 3].

After rotating a sorted array, Aahad needs to answer Q queries asked by Harshit, each of them is described by one integer Q[i]. which Harshit wanted him to search in the array. For each query, if he found it, he had to shout the index of the number, otherwise, he had to shout -1.

For each query, you have to complete the given method where 'key' denotes Q[i]. If the key exists in the array, return the index of the 'key', otherwise, return -1.

Note:

Can you solve each query in O(logN) ?