Software Engineer

A Derangement is a permutation of ‘N’ elements, such that no element appears in its original position. For example, an instance of derangement of {0, 1, 2, 3} is {2, 3, 1, 0}, because 2 present at index 0 is not at its initial position which is 2 and similarly for other elements of the sequence.

Given a number ‘N’, find the total number of derangements possible of a set of 'N’ elements.

Note:

The answer could be very large, output answer %(10 ^ 9 + 7).

You have been given an array/list 'ARR' consisting of 'N' integers. Your task is to find the majority element in the array. If there is no majority element present, print -1.

Note:

A majority element is an element that occurs more than floor('N' / 2) times in the array.

Given an array of size 'N' return the count array such that COUNT[i] equals the number of element which are smaller than ARR[ i ] on its the right side.

For Example : ARR = [4,2,1,5] the count array corresponding to the given array is :-.

The Number of elements smaller than 4 on its right side is 2.
The Number of elements smaller than 2 on its right side is 1.
The Number of elements smaller than 1 on its right side is 0.
The Number of elements smaller than 5 on its right side is 0.
Hence the count array is [2,1,0,0]

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You are given an array “A” of N integers. Your task is to find the maximum element in all K sized contiguous subarrays from left to right.

For Example:

If A = [3, 2, 3], and K = 2.
Then max of [3, 2] = 3 and max of [2, 3] = 3
So, the answer will be [3, 3]

If A = [3, 2, 3, 5, 1, 7] and K = 3.
Then max of [3, 2, 3] = 3 
Then max of [2, 3, 5] = 5 
Then max of [3, 5, 1] = 5 
Then max of [5, 1, 7] = 7 
So  the answer will be [3, 5, 5, 7]

Follow Up :

Can you solve the problem in O(N) time complexity and O(K) space complexity?

You have been given the preorder and inorder traversal of a binary tree. Your task is to construct a binary tree using the given inorder and preorder traversals.

Note:

You may assume that duplicates do not exist in the given traversals.

For example :

For the preorder sequence = [1, 2, 4, 7, 3] and the inorder sequence = [4, 2, 7, 1, 3], we get the following binary tree.

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