Product Engineer

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You have been given a Binary Tree of 'n' nodes, where the nodes have integer values

Print the left view of the binary tree.

Example :

If the input tree is as depicted in the picture: 

The Left View of the tree will be:  2 35 2 

You are given an array/list 'ARR' consisting of N integers, which contains elements only in the range 0 to N - 1. Some of the elements may be repeated in 'ARR'. Your task is to find all such duplicate elements.

Note:

1. All the elements are in the range 0 to N - 1.
2. The elements may not be in sorted order.
3. You can return the duplicate elements in any order.
4. If there are no duplicates present then return an empty array.

Given an array of numbers, find the maximum sum of any contiguous subarray of the array.

For example, given the array [34, -50, 42, 14, -5, 86], the maximum sum would be 137, since we would take elements 42, 14, -5, and 86.

Given the array [-5, -1, -8, -9], the maximum sum would be -1.

Follow up: Do this in O(N) time.

You have been given two Strings “STR1” and “STR2” of characters. Your task is to find the length of the longest common subsequence.

A String ‘a’ is a subsequence of a String ‘b’ if ‘a’ can be obtained from ‘b’ by deletion of several (possibly, zero or all) characters. A common subsequence of two Strings is a subsequence that is common to both Strings.

You are given a string 'str' of length 'N'.

Your task is to reverse the original string word by word.

There can be multiple spaces between two words and there can be leading or trailing spaces but in the output reversed string you need to put a single space between two words, and your reversed string should not contain leading or trailing spaces.

Example :

If the given input string is "Welcome to Coding Ninjas", then you should return "Ninjas Coding to Welcome" as the reversed string has only a single space between two words and there is no leading or trailing space.

Which tech stack have you worked on ?

Design a parking lot system.

What are ACID properties.

What is an Inner Join?

You are given a string ‘expression’ consists of characters ‘+’, ‘-’, ‘*’, ‘/’, ‘(‘, ‘)’ and ‘0’ to ‘9’, that represents an Arithmetic Expression in Infix Notation. Your task is to evaluate this Arithmetic Expression.

In Infix Notation, operators are written in-between their operands.

Note :

1. We consider the ‘/’ operator as the floor division.

2. Operators ‘*’ and ‘/’ expression has higher precedence over operators‘+’ and ‘-’ 

3. String expression always starts with ‘(‘ and ends with ‘)’.

4. It is guaranteed that ‘expression’ represents’ a valid expression in Infix notation.

5. It is guaranteed that there will be no case that requires division by 0.

6. No characters other than those mentioned above are present in the string. 

7. It is guaranteed that the operands and final result will fit in a 32-bit integer.

For example :

Consider string ‘expression’ = ‘((2+3)*(5/2))’. 
Then it’s value after evaluation will be ((5)*(2)) = 10. 

We are suffering from the Second wave of Covid-19. The Government is trying to increase its vaccination drives. Ninja wants to help the Government to plan an effective method to help increase vaccination following safety measures. Time is running out. Can you help the nation?

You are given two positive integers: ‘n,’ ‘maxVaccines’ denoting the number of days for which this vaccination drive will go on and the total number of vaccines available for the drive, respectively. You have to find the number of vaccines administered each day. You are also given a number ‘dayNumber,’ and we are interested to know the maximum number of vaccines that can be administered on ‘dayNumber’ th day.

The rules of the vaccination drive :

1. There should be a positive number of vaccines administered each day during the vaccination drive.

2. The absolute difference between the number of vaccines in two consecutive days should not exceed 1.

3. The sum of all the elements of the vaccines array does not exceed maxVaccines, that is, you cannot administer more vaccines than what is provided to you.

4. Vaccines administered on ‘dayNumber’ th day should be maximized.

They give a problem statement and ask to create different APIs according to the requirements. Also create db tables for the same. The APIs might need to join two tables.

What are the top 3 things you look for in a job?

Why do you want change?