SDE - 1

Given a binary tree of nodes 'N', you need to modify the value of its nodes, such that the tree holds the Children sum property.

A binary tree is said to follow the children sum property if, for every node of that tree, the value of that node is equal to the sum of the value(s) of all of its children nodes( left child and the right child).

Note :

 1. You can only increment the value of the nodes, in other words, the modified value must be at least equal to the original value of that node.
 2. You can not change the structure of the original binary tree.
 3. A binary tree is a tree in which each node has at most two children.      
 4. You can assume the value can be 0 for a NULL node and there can also be an empty tree.

You are given three strings “A”, “B” and “C”. Your task is to check whether “C” is formed by an interleaving of A and B. C is said to be interleaving “A” and “B”, if the length of “C” is equal to the sum of the length of A and length of B, all the characters of “A” and “B” are present in “C”, and the order of all these characters remains the same in all three strings.

For Example:

If A = “aab”, B = “abc”, C = “aaabbc”
Here C is an interleaving string of A and B. Because C contains all the characters of A and B and the order of all these characters is also the same in all three strings.

If A = “abc”, B = “def”, C = “abcdefg”
Here C is not an interleaving string of A and B as neither A nor B contains the character ‘g’.

You are given two strings 'str1' and 'str2'. Find the minimum operations required to convert str1 into str2.

An Operation is defined as:

A character from an index of a string(str1) is put at the end of it, is defined as a single operation.

 Note :

You cannot perform any operation on the string, str2.

You are given a 2D board('N' rows and 'M' columns) of characters and a string 'word'.

Your task is to return true if the given word exists in the grid, else return false. The word can be constructed from letters of sequentially adjacent cells, where adjacent cells are horizontally or vertically neighboring.

Note:

The same letter cell should not be used more than once.

For Example:

For a given word “design” and the given 2D board 
[[q’, ‘v’, ‘m’, ‘h’],
 [‘d’, ‘e’, ‘s’, ‘i’],
 [‘d’, ‘g’, ‘f’, ‘g’],
 [‘e’, ‘c’, ‘p’, ‘n’]]

The word design can be formed by sequentially adjacent cells as shown by the highlighted color in the 2nd row and last column.

Asked me to design the feed pipeline of sharechat. It was more of an HLD discussion.
Further asked me more about caching and it's implementation.

You will be given ‘Q’ queries. You need to implement a circular queue according to those queries. Each query will belong to one of these two types:

1 ‘X’: Enqueue element ‘X’ into the end of the nth queue. Returns true if the element is enqueued, otherwise false.

2: Dequeue the element at the front of the nth queue. Returns -1 if the queue is empty, otherwise, returns the dequeued element.

Note:

Enqueue means adding an element to the end of the queue, while Dequeue means removing the element from the front of the queue.

How will you search words in an efficient manner?

An in-depth discussion on my current project.