SDE

You are given an array 'arr' of strings, where each string consists of English lowercase letters.

A string chain of 'arr' is defined as:

(1) A sequence of string formed using elements of 'arr'.

(2) Every string in the sequence can be formed by inserting a lowercase English letter into the previous string (except the first string).

Find the length of the longest possible string chain of 'arr'.

Example :

Input: 'arr' = ["x", "xx", "y", "xyx"] 

Output: 3

Explanation:
The longest possible string chain is “x” -> “xx” -> “xyx”.
The length of the given chain is 3, hence the answer is 3.

You are given a non-empty binary tree where each node has a non-negative integer value. Return the maximum possible sum of path between any two leaves of the given tree.

The path is also inclusive of the leaf nodes and the maximum path sum may or may not go through the root of the given tree.

If there is only one leaf node in the tree, then return -1.

Given a binary tree with ‘root’. Your task is to find the sum of all the left leaf nodes.

Properties of leaf:-

In a binary tree, a leaf is a node such that it does not have any children. Node ‘1’ is always the root of the binary tree. Left leaves are those nodes that are the left child of their parent and a leaf node.

Example:

Let’s say you have a binary tree as follows:-

Node 4 and Node 5 are leaf nodes and left child of their parent. Node 6 is a leaf node but not the left child of its parent node 3. Therefore return ‘4+5= 9’ as the answer.

Note:

You do not need to print anything; it has already been taken care of. Just implement the function.

You are given a positive integer 'N'. Your task is to find the number of strings of length ‘N’ that can be formed using only the characters ‘a’, ‘b’ and ‘c’. The strings formed should be such that the number of ‘b’ and ‘c’ in the string is at most 1 and 2, respectively.

Example:

Let’s say N = 2. The strings of length 2, which satisfy the given constraints are: “aa”, “ab”, “ac”, “ba”, “bc”, “ca”, “cb”, “cc”. Hence, the output is 8.

What do you mean by Semaphore in OS? Why is it used?

What is a deadlock in OS? What are the necessary conditions for a deadlock?

What are your strengths and weaknesses?

Why do you want to join us?

Introduction.

Previous Work experiences.

Questions related to Projects.

How do I manage time?