Software Engineer

The idea is to split the problem into 3 parts:
• Print the left boundary in a top-down manner.
• Print the leaf nodes in the same order as in the inorder traversal.
• Print the right boundary in a bottom-up manner.
Time Complexity : O(N) 

Two edge cases need to be taken care of : 
1. Both the left boundary and the right boundary traversal prints the root node. To avoid this, print the root node first and then perform left and right boundary traversal on left and right child respectively. 
2. The leftmost and the rightmost node of the binary tree are leaf nodes. They will get printed while performing the left boundary and the right boundary traversal while printing the leaf nodes. To avoid it, exclude the leaf nodes while doing the left boundary and the right boundary traversal.

BFS can be used to find the cell which is reachable from the bomb and farthest from the bomb. 
Start the BFS from the location at expanding to the four adjacent cells if there are not visited so far. 
For each cell, also maintain the smallest distance from the bomb. 

Algorithm:
1. Initialize Distace[N][M] to infinity.
2. Initialise Distace[X][Y] to 1.
3. Queue = [(X, Y)] : This queue stores all the unprocessed cells, we will pop a cell from the queue and try to move to an adjacent cell
4. Initially, Ans = -1. Ans stores the final answer 
5. While (size of Queue > 0)
a, b = Queue.pop()
ans=Distance[a][b]
For all not visited adjacent cells
If Grid[a][b]==0 and Distance[a][b]== infinity
Try to visit all the adjacent cells if the distance of adjacent cells is infinity then this cell is not visited yet 
Distance[adjacent-x][adjacent-y]=Distance[a][b]+1
Queue.push((ad-x,ad-y)) : Addd the adjacent the cell to queue

Time Complexity : O(N*M) where ‘N’, ‘M’, is the dimensions of the room.
Space Complexity : O(N*M) where ‘N’, ‘M’, is the dimensions of the room.

Tip 1  : Firstly, remember that the system design round is extremely open-ended and there’s no such thing as a standard answer. Even for the same question, you’ll have a totally different discussion with different interviewers.

Tip 2 : Before you jump into the solution always clarify all the assumptions you’re making at the beginning of the interview. Ask questions to identify the scope of the system. This will clear the initial doubt, and you will get to know what are the specific detail interviewer wants to consider in this service.

Tip 3 : Design your structure and functions according to the requirements and try to convey your thoughts properly to the interviewer so that you do not mess up while implementing the idea .

In traditional programming, the flow of the business logic is determined by objects that are statically assigned to one another. With inversion of control, the flow depends on the object graph that is instantiated by the assembler and is made possible by object interactions being defined through abstractions. The binding process is achieved through dependency injection, although some argue that the use of a service locator also provides inversion of control.

Inversion of control as a design guideline serves the following purposes :
There is a decoupling of the execution of a certain task from implementation.
Every module can focus on what it is designed for.
Modules make no assumptions about what other systems do but rely on their contracts.
Replacing modules has no side effect on other modules.

The command pattern is a behavioral design pattern and is part of the GoF‘s formal list of design patterns. Simply put, the pattern intends to encapsulate in an object all the data required for performing a given action (command), including what method to call, the method's arguments, and the object to which the method belongs.
This model allows us to decouple objects that produce the commands from their consumers, so that's why the pattern is commonly known as the producer-consumer pattern.