SDE - 1

You have been given an array/list 'HEIGHTS' of length ‘N. 'HEIGHTS' represents the histogram and each element of 'HEIGHTS' represents the height of the histogram bar. Consider that the width of each histogram is 1.

You are supposed to return the area of the largest rectangle possible in the given histogram.

For example :

In the below histogram where array/list elements are {2, 1, 5, 6, 2, 3}.

The area of largest rectangle possible in the given histogram is 10.

A permutation is a mathematical technique that determines the number of possible arrangements in a set when the order of the arrangements matters. A string of length 'N' has 'N'! permutations.

Given an array of distinct integers, return all the possible permutations of the array.

Example:

'ARR[]' = [1, 2]

The size of the array is 2. So, the total number of permutations is 2! = 2. The possible permutations are [1, 2] (the array itself) and [2,1] where the position of element 1 in the original array is swapped with element 2 and vice-versa.   

Note:

1. All the numbers in the array are unique.

2. You can return the answer in any order.

3. The original array is also a permutation of the given array.

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You are given a Singly Linked List of integers. You have to find the N-th node from end.

For Example

If the given list is (1 -> -2 -> 0 -> 4) and N=2:

Then the 2nd node from the end is 0.

Given 'k' sorted linked lists, each list is sorted in increasing order. You need to merge all these lists into one single sorted list. You need to return the head of the final linked list.

For example:

Input:
3
3
4 6 8
3
2 5 7 
2
1 9

Output:
1 2 4 5 6 7 8 9 

Explanation:
First list is: 4 -> 6 -> 8 -> NULL
Second list is: 2 -> 5 -> 7 -> NULL
Third list is: 1 -> 9 -> NULL
The final list would be: 1 -> 2 -> 4 -> 5 -> 6 -> 7 -> 8 -> 9 -> NULL

You are given a multicore server and a distributed queue. You need to fetch elements from the queue and store them into the database.

A solution was suggested of running a master thread, which checks the queue and allocates more threads for processing entries.