SDE - 1

You have been given a grid containing some oranges. Each cell of this grid has one of the three integers values:

Value 0 - representing an empty cell.

Value 1 - representing a fresh orange.

Value 2 - representing a rotten orange.

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

Your task is to find out the minimum time after which no cell has a fresh orange. If it's impossible to rot all the fresh oranges then print -1.

Note:

1. The grid has 0-based indexing.
2. A rotten orange can affect the adjacent oranges 4 directionally i.e. Up, Down, Left, Right.

You have been given a linked list of integers. Your task is to write a function that deletes a node from a given position, 'POS'.

Note :

Assume that the Indexing for the linked list always starts from 0.

If the position is greater than or equal to the length of the linked list, you should return the same linked list without any change.

Illustration :

The following images depict how the deletion has been performed.

Image-I :

Image-II :

You have been given an array/list 'WORDS' of 'N' non-empty words, and an integer 'K'. Your task is to return the 'K' most frequent words sorted by their frequency from highest to lowest.

Note:

If two words have the same frequency then the lexicographically smallest word should come first in your answer.

Follow up:

Can you solve it in O(N * logK) time and O(N) extra space? 

Which is the best data structure that could used in any case? Why did you choose it?
Which data structure could be used in a scenario where several entities that are connected to each other, like facebook? Why?

You are Harshad Mehta’s friend. He told you the price of a particular stock for the next ‘n’ days.

You are given an array ‘prices’ which such that ‘prices[i]’ denotes the price of the stock on the ith day.

You don't want to do more than 2 transactions. Find the maximum profit that you can earn from these transactions.

Note

1. Buying a stock and then selling it is called one transaction.

2. You are not allowed to do multiple transactions at the same time. This means you have to sell the stock before buying it again. 

Example:

Input: ‘n’ = 7, ‘prices’ = [3, 3, 5, 0, 3, 1, 4].

Output: 6

Explanation: 
The maximum profit can be earned by:
Transaction 1: Buying the stock on day 4 (price 0) and then selling it on day 5 (price 3). 
Transaction 2: Buying the stock on day 6 (price 1) and then selling it on day 6 (price 4).
Total profit earned will be (3 - 0) + ( 4 - 1) = 6.