Software Engineer

You are given the ‘ROOT’ of a binary tree with ‘N’ nodes where each node in the tree has some coins, and there are ‘N’ coins total. In one move, we may choose two adjacent nodes and move one coin from one node to another.

Your task is to return the number of moves required to make every node have exactly one coin.

Note:

A move may be from parent to child or from child to parent.

For example,

Given ‘ROOT’ = [2,-1,0,-1,-1]

The tree would look like this : 

The answer would be 1, because the root node will transfer 1 coin to its right child. Thus both nodes have the same number of coins now.

Given an array arr of N integers that may contain duplicate integers. The task is to return the count of subsets of the given array such that each subset contains only distinct elements.

Note:

As the answer can be large, return your answer modulo 10^9  + 7. 

A thief is robbing a store and can carry a maximal weight of W into his knapsack. There are N items and the ith item weighs wi and is of value vi. Considering the constraints of the maximum weight that a knapsack can carry, you have to find and return the maximum value that a thief can generate by stealing items.

You have been given an unsorted array ‘ARR’.

Your task is to sort the array in such a way that the array looks like a wave array.

Example:

If the given sequence ‘ARR’ has ‘N’ elements then the sorted wave array looks like - 
‘ARR[0] >= ARR[1]’ and ‘ARR[1] <= ARR[2]’
‘ARR[2] >= ARR[3]’ and ‘ARR[3] <= ARR[4]’
‘ARR[4] >= ARR[5]’ and ‘ARR[5] <= ARR[6]’  And so on.

Note:

1. ‘ARR[0]’ must be greater than or equal to ‘ARR[1]’.

2. There can be multiple arrays that look like a wave array but you have to return only one.

3. We have an internal function that will check your solution and return 'True' in case your array is one of the solutions otherwise return 'False'.

Explanation

The given array ‘ ARR = { 4, 3, 5, 2, 3, 1, 2 } ’
The below figure is a visual representation of the given ‘ARR’ and you can see we can express ‘ARR’ in a waveform array because 
4>3 and 3<5 
5>2 and 2<3
3>1 and 1<2
And it follows the condition of wave array.

Follow up:

Try to solve this problem in linear time complexity.

You are given a Singly Linked List of integers. You need to reverse the Linked List by changing the links between nodes.

Note :

You do not need to print anything, just return the head of the reversed linked list. 

Assuming the best cricketer playing with the best strategy. How many maximum runs he can score in ipl satisfying all rules of cricket and NO wide balls.

What is virtual memory .
What are page faults.
What is kernel

You are given a stream of 'N' integers. For every 'i-th' integer added to the running list of integers, print the resulting median.

Print only the integer part of the median.

LRU Cache Implementation

Design a stack that supports getMin() in O(1) time and O(1) extra space

What is segementation.
Difference between internal and external fragmetation

SQL command
ACID properties
Difference between unique primary and foreign key.