SDE - Intern

This Round consists of 50 MCQs questions Out of Which 40 were related to basic programming questions and 10 were related to aptitude. some questions were output bases. Also, there was negative marking too.

Number Of MCQs - 50

Given a string input of length n, find the length of the longest substring without repeating characters i.e return a substring that does not have any repeating characters.

Substring is the continuous sub-part of the string formed by removing zero or more characters from both ends.

Given a binary tree of integers, you are supposed to modify the given binary tree to a sum tree where each node value is replaced by the sum of the values of both left and right subtrees in the given tree. The value of leaf nodes is changed to zero.

Example:

Below is the example showing the input tree and its sum tree.  

You are given a binary tree, where the data present in each node is an integer. You have to find whether the given tree is symmetric or not.

Symmetric tree is a binary tree, whose mirror image is exactly the same as the original tree.

For Example:

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.

You have been given a circular path. There are 'N' petrol pumps on this path that are numbered from 0 to N - 1 (Both inclusive). Each petrol pump has two values associated with it:

1)The amount of petrol that is available at this particular petrol pump.
2)The distance to reach the next petrol pump.

You are on a truck having an empty tank of infinite capacity. You can start the tour from any of the petrol pumps. Your task is to calculate the first petrol pump from where the truck will be able to complete the full circle or determine if it is impossible to do so.

You may assume that the truck will stop at every petrol pump and it will add the petrol from that pump to its tank. The truck will move one kilometre for each litre of petrol consumed.

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 Binary Tree ‘root’. The given Binary Tree may or may not be a Binary Search Tree(BST) itself. Your task is to find the maximum sum of node values of any subtree that is a Binary Search Tree(BST).

Binary Search Tree is defined as follows:

1) If the left subtree exists it should contain only nodes with values less than the current node's value.

2) If the right subtree exists it should contain only nodes with values greater than the current node's value.

3) Both the left and right subtrees should also be Binary Search Tree.

Example :

For the above binary tree, the BST with the maximum possible sum is marked with RED colour, the sum of this BST is equal to 6.

Given a Binary Search Tree (BST) and a range [min, max], remove all keys which are outside the given range. The modified tree should also be BST.

You are given the ‘root’ of a Balanced Binary Search Tree and an integer ‘target,’ you have to tell if there exists any pair of nodes such that the sum of their value is equal to the target.

More formally check if there exist any two distinct nodes, whose sum is equal to ‘target.’

Note:

A binary search tree, also called an ordered or sorted binary tree, is a rooted binary tree whose internal nodes each store a key greater than all the keys in the node's left subtree and less than those in its right subtree.

A balanced binary search tree is a tree in which each node has either 0 or 2 children.

Example:

For Example, the root node is given as follows :
‘ROOT’ = 5 2 6 -1 -1 -1 -1 and ‘target’ = 8, The answer will be true since the sum of both leaf nodes is equal to 8.

There are 'N' number of subjects and the ith subject contains subject[i] number of problems. Each problem takes 1 unit of time to be solved. Also, you have 'K' friends, and you want to assign the subjects to each friend such that each subject is assigned to exactly one friend. Also, the assignment of subjects should be contiguous. Your task is to calculate the maximum number of problems allocated to a friend is minimum. See example for more understanding.

For Example:

If N = 4, K = 2 and subjects = {50,100,300,400}
Assignment of problems can be done in the following ways among the two friends.
{} and {50,100,300,400}. Time required = max(0, 50+100+300+400) = max(0, 850) = 850
{50} and {100,300,400}. Time required = max(50, 100+300+400) = max(50, 800) = 800
{50, 100} and {300,400}. Time required = max(50+100, 300+400) = max(150, 700) = 700
{50,100,300} and {400}. Time required = max(50+100+300, 400) = max(450, 400) = 400
{50,100,300, 400} and {}. Time required = max(50+100+300+400, 0) = max(850, 0) = 850

So, out of all the above following ways, 400 is the lowest possible time.

How was your Day?

Tell me about Yourself.

2 strengths and weaknesses.

How many members in your family?

Can you work form office?