SDE - Intern

You are provided with a Binary Tree and one of its leaf nodes. You have to invert this binary tree. Inversion must be done by following all the below guidelines:

• The given leaf node becomes the root after the inversion.

• For a node (say, ‘x’) 
    ○ If there exists the left child that is not yet taken then this child must become the right child of ‘x’.
    ○ If the left child is already taken then the right child is still on the right side of ‘x’.

• The parent of ‘x’ must be the left child of ‘x’.

For Example:

Consider the above binary tree (image- before inversion), if the given leaf node is ‘1’ then the binary tree after inversion becomes exactly the same as given in the image representing after inversion.

Note:

The given binary tree will only have distinct values of nodes.

You have been given a non-empty grid consisting of only 0s and 1s. You have to find the number of islands in the given grid.

An island is a group of 1s (representing land) connected horizontally, vertically or diagonally. You can assume that all four edges of the grid are surrounded by 0s (representing water).

You are given an arbitrary binary tree, a node of the tree, and an integer 'K'. You need to find all such nodes which have a distance K from the given node and return the list of these nodes.

Distance between two nodes in a binary tree is defined as the number of connections/edges in the path between the two nodes.

Note:

1. A binary tree is a tree in which each node has at most two children. 
2. The given tree will be non-empty.
3. The given tree can have multiple nodes with the same value.
4. If there are no nodes in the tree which are at distance = K from the given node, return an empty list.
5. You can return the list of values of valid nodes in any order. For example if the valid nodes have values 1,2,3, then you can return {1,2,3} or {3,1,2} etc.

Example :

Consider this tree above. The target node is 5 and K = 3. The nodes at distance 1 from node 5 are {2}, nodes at distance 2 from node 5 are {1, 4} and nodes at distance 3 from node 5 are {6, 3}.

Given an integer array 'ARR' of size 'N' and an integer 'K', return all the subsets of 'ARR' which sum to 'K'.

Subset of an array 'ARR' is a tuple that can be obtained from 'ARR' by removing some (possibly all) elements of 'ARR'.

Note :

The order of subsets is not important. 

The order of elements in a particular subset should be in increasing order of the index.

It was like a rapid-fire round, to be honest. The interviewer shooted around 15-20 questions related to OS and OOPS within a span of 10 minutes. The questions were of very basic type and a bit medium. Topics include semaphore, paging, virtual memory, bankers algo, deadlock conditions, ram vs rom, class vs struct, polymorphism etc.