Application Development Associate

You are given a list of a repeated set of integers. Your task for the problem is to return a list of the given elements in decreasing sorted order of their frequency of repetition in the given list with the element with the highest frequency of repetition first and so on.

Note :

If two numbers have the same frequency then keep the one that was present before the other in the original given list (array) first.

For Example :

Input:  arr[] = {2, 5, 2, 8, 5, 6, 8, 8}
Output: arr[] = {8, 8, 8, 2, 2, 5, 5, 6}

Explanation :
When you sort the array based on the decreasing order of the frequency of repetition of integers in the original array, 
you’ll find that the element ‘8’ is the integer with the most repeated values therefore it would be arranged first after which since both 2 and 5 have the same number of repeated 
values in the original array but since the 2 arrived first so we will first arrange 2 and then 5 in our resultant array, while would be the last element after sorting here.

You are given a singly linked list ‘HEAD’ consisting of ‘N’ nodes. The task is to group all the odd nodes together, followed by the even nodes, maintaining the relative order of nodes given in the input. Note that we are talking about the node’s positions and not the value stored in the node. Try to write an in-place algorithm (i.e., without using any extra space) to solve this problem.

Example:

Given linked list: ‘2 => 1 => 3 => 4 => 6 => 5’

While maintaining the relative order of nodes as it is in the input, Nodes at odd positions are (2, 3, 6), and nodes at evens position are (1, 4, 5).

Modified linked list: ‘2 => 3 => 6 => 1 => 4 => 5’

Note:

1. Consider that the first node is odd, the second is even, and so on.

Given an AVL tree, insert an element in the AVL Tree.

An AVL tree is a self-balancing binary search tree.

It has the following properties:

1. It has the property of the binary search tree , i.e for every node , the nodes in its left subtree is less than the node and nodes in the right subtree is greater than the current node.

2. The absolute difference between the height of left subtree and right subtree of any node is less than or equal to 1.

Read more about AVL Tree Here: https://en.wikipedia.org/wiki/AVL_tree

For example:

The numbers in white beside the nodes denote the height of the tree. We can see when we insert 7 in the tree it imbalances the tree at node 10 and hence we do a rotation to rebalance it. FInally we return the in order traversal of the final tree.

Note

1.Do not print anything, just return the root node of the tree.
2.Your constructed tree will be checked by doing an in-order traversal of the tree from the returned root node.

You are given an integer 'N'. For a given 'N' x 'N' chessboard, find a way to place 'N' queens such that no queen can attack any other queen on the chessboard.

A queen can be killed when it lies in the same row, or same column, or the same diagonal of any of the other queens. You have to print all such configurations.

You are given an array/list ARR consisting of N integers. Your task is to find all the distinct triplets present in the array which adds up to a given number K.

An array is said to have a triplet {ARR[i], ARR[j], ARR[k]} with sum = 'K' if there exists three indices i, j and k such that i!=j, j!=k and i!=j and ARR[i] + ARR[j] + ARR[k] = 'K'.

Note:

1. You can return the list of values in any order. For example, if a valid triplet is {1, 2, -3}, then {2, -3, 1}, {-3, 2, 1} etc is also valid triplet. Also, the ordering of different triplets can be random i.e if there are more than one valid triplets, you can return them in any order.
2. The elements in the array need not be distinct.
3. If no such triplet is present in the array, then return an empty list, and the output printed for such a test case will be "-1".

You are given an array arr consisting of ‘N’ integers. Your task is to find the largest number, ‘K’, such that both the values ‘K’ and -‘K’ are present in the given array 'arr'. If no such number exists, then return '-1'.

For example:

Consider ‘arr’ = [1,2,-2,-1], the largest value of ‘K’ is 2, since a negative of 2 is also present in the array. Hence, the answer is 2.

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