Software Engineer

A jeweler was stuck in a 2D maze. The maze is in the form of a 2D matrix of size ‘N’ * ‘N’. Each cell in the maze had three possibilities, 0, 1, -1. 0 means that the cell is empty, 1 means that the cell has a piece of gold, and -1 means that the cell is blocked. The jeweler wants to travel from the upper left corner (0, 0) to the lower right corner(N -1, N - 1) and return back again to (0, 0). Help the jeweler to collect the maximum amount of gold.

Note:

While moving towards the lower right corner, he can only go in two directions, i.e., right and down and while returning, he can only move in the directions left and up.

If there is no valid path, he cannot collect any gold.

For Example :

N = 3, mat = {{1, 1, 1}, {0, -1, 0,}, {1, 1, 1}}

In this example, the jeweler will first follow the path: (0, 0) -> (0, 1) -> (0, 2) -> (1, 2)  -> (2, 2) and then return from the path (2, 2) -> (2, 1) -> (2, 0) -> (1, 0) -> (0, 0). Hence the total gold collected will be 6.

Given a maze in the form of a binary rectangular matrix of size M*N, where each element can either be 0 or 1, the task is to find the length of the shortest path in a maze from a given source cell to a destination cell.

The path can only be created out of a cell if its value is 1 and at any given moment, we can only move one step in one of the four directions. The valid moves are:

Up: (x, y) -> (x - 1, y)
Left: (x, y) -> (x, y - 1)
Down: (x, y) -> (x + 1, y)
Right: (x, y) -> (x, y + 1)

If there is no path from a given source cell to a destination cell, return -1.

For example :

consider the binary matrix below. If source = (0, 0) and destination = (3, 4), the shortest path from source to destination has length 11.

Ninja was playing with the nodes of the BST (Binary Search Tree). He found that after insertion of some nodes, he was unable to insert any more nodes to a leaf node. In such a scenario he termed the BST as Dead End. He has many sets of BST, it is very difficult for him to individually find whether a BST is Dead End or not. He asked you to design an algorithm to find whether a given Binary Search Tree (BST) containing positive integers only is Dead End or not.

Note: A BST is said to be Dead End if there exists a leaf node in the BST, for which it is impossible to insert any further nodes after that node in that BST. If such nodes do not exist, then the BST is not said to be Dead End.

A binary search tree (BST) is a binary tree data structure with the following properties.

• The left subtree of a node contains only nodes with data less than the node’s data.

• The right subtree of a node contains only nodes with data greater than the node’s data.

• Both the left and right subtrees must also be binary search trees.

Explain OOPS Concepts.

What are ACID properties?

What are joins?

What keeps you motivated?

Who is your role model?