SDE - 1

Given a binary tree, convert this binary tree into its mirror tree.

A binary tree is a tree in which each parent node has at most two children.

Mirror of a Tree: Mirror of a Binary Tree T is another Binary Tree M(T) with left and right children of all non-leaf nodes interchanged.

Note:

1. Make in-place changes, that is, modify the nodes given a binary tree to get the required mirror tree.

You live in a Ninja town which is in the form of a N * M grid. In this town, people travel from one place to another by jumping over the buildings which are present in each cell of the grid. It is Christmas eve, and Santa wants to give gifts and chocolates to the kids who live in the building which is present at the cell (N - 1, M - 1). Initially, Santa is present on cell (0, 0). Since Santa is in a hurry, help him find a path from starting point to the endpoint with the least amount of time.

The Santa may go only from one building to any of its adjacent buildings which is present either to the right or to the bottom or bottom right cell i.e. if the current position is (x, y), he may go to (x + 1, y + 1) or (x + 1, y) or (x, y + 1) given that the new coordinates are in the grid. The time taken to reach from one building to another is equal to the absolute difference between the heights of buildings.

Note:

1. The heights of the buildings are positive.
2. Santa starts from the cell (0, 0) and he has to reach the building (N - 1, M - 1).
3. Santa cannot leave the grid at any point of time.

You are given two strings 'str1' and 'str1'.

You have to tell whether these strings form an anagram pair or not.

The strings form an anagram pair if the letters of one string can be rearranged to form another string.

Pre-requisites:

Anagrams are defined as words or names that can be formed by rearranging the letters of another word. Such as "spar" can be formed by rearranging letters of "rasp". Hence, "spar" and "rasp" are anagrams. 

Other examples include:

'triangle' and 'integral'
'listen' and 'silent'

Note:

Since it is a binary problem, there is no partial marking. Marks will only be awarded if you get all the test cases correct. 

You are given an array of 'N' integers denoting the heights of the mountains. You need to find the length of the longest subarray which has the shape of a mountain.

A mountain subarray is defined as a subarray which consists of elements that are initially in ascending order until a peak element is reached and beyond the peak element all other elements of the subarray are in decreasing order.

Example:

If the given array is: [1 3 1 4]. The longest mountain subarray would be 3. This is because the longest mountain is  [1 3 1] having length 3.

Build the db design for an e-commerce application.
Functionalities:
Users can order a product.
A product can have multiple categories.
Users should be able to order multiple products and pay for it.
The application should be able to handle the inventory of products.

Think about Data modeling, Data querying and how will you build this application for the end-user?
Also, the system should be highly available and resilient to failures.

A man is walking down the village road with a tiger, a goat, and a bundle of grass. Soon he arrives at the river bank where there is one tiny boat that can carry him and another animal or grass at a time. Here is the problem: Left alone, the tiger will eat the goat. And similarly, the goat will eat the grass bundle. How is he going to take all three across the river safely?