SDE - 1

You have a 2D grid of ‘N’ rows and ‘M’ columns which are initially filled with water. You are given ‘Q’ queries each consisting of two integers ‘X’ and ‘Y’ and in each query operation, you have to turn the water at position (‘X’, ‘Y’) into a land. You are supposed to find the number of islands in the grid after each query.
An island is a group of lands surrounded by water horizontally, vertically, or diagonally.

You are given an array of integers of size ‘N’. You have to make the elements of the array equal, and the cost of changing the element ‘x’ to ‘y’ is abs(x -y). Your task is to find the minimum cost to make the elements of the array equal.
For Example:
Consider ARR = [3, 4, 5] now suppose if we want to change every element value to 4, then the cost of changing 3 to 4 is |3 - 4| which is 1, and the cost of changing 5 to 4 is |5 - 4| which is 1, so the total cost is 1 + 1 = 2. The value 2 is the minimum cost to make all values in the array equal. Hence, the answer is 2.

Things to discuss and analyze: 

Approach for one-on-one text messaging between users.
Approach for extending the design to support group chats.
Delivered and read status
What action needs to be taken if the user is not connected to the internet?
Push notifications
Sending media like images or other documents
Approach for providing end-to-end message encryption.

In concurrent computing, deadlock is any situation in which no member of some group of entities can proceed because each waits for another member, including itself, to take action, such as sending a message or, more commonly, releasing a lock.