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Product Developer was asked...19 December 2017

### write a singleton class in c++

2 Answers

Can you pls give me your fb id or any other contact details

Need some help about interview

### what is difference between sales and marketing why should we hire you

2 Answers

Sales and marketing are interlinked,marketing is just like a study involving of customer mode,advertising, branding,making leads Whereas sales turns the leads to the products..When there is no product there is no need for a lead this is how they are interlinked Less

Sales is give your product's ownership to another person and marketing is all about customers need and satisfying them. I recently leave E-learning industry. Now I want to go with my passion and I want work with e-learning industry ever. Less

### Find the kth minimum element in an array without sorting

2 Answers

If the array is not sorted then we can use min heap to get kth smallest element. 1. Forming a Min heap O(n logn) complexity. 2. For values 1 to k, remove elements from root and re-form the heap O(k logn) complexity Less

If it is not so stressed on time complexity, we can find it in O(n^2). Use two loops. Outer loop will take element one by one sequentially from 0 to n-1 and second loop will run from 0 to n-1 finding whether the arr[i] &gt; arr[j], if so have a count array and increment it based on i. Finally loop through the count array and find which one is equal to k and display that value in arr. Less

### 1c) Given an array of of 0,1,2 sort the array maintaining the position of the elements, i.e, the 1 appeared at index 2 should come first before the 1 at index 5, when sorted.

2 Answers

Count sort is a better solution since the array contains repeated numbers from a range. Complexity would be O(n+k) where k is the range of numbers(3 in this case). Less

Said Insertion Sort algorithm.

### It includes basic concepts, IPC, OS fundamentals. Given some real world problem scenarios, how you will solve it.

2 Answers

after telephonic interview, in how much time they will call Back for face to face interview? Less

After telephonic interview, in how much time they will call back to you for face to face interview? Less

### what is semaphore

2 Answers

Semaphore is a variable used for handling mutual exclusion in parallel processing. Following operations are defined over a semaphore. notify() - thread has released the given resource. Decrease semaphore count. wait() - Thread has acquired the given resource. Increase semaphore count. Access is granted to a thread only if value of semaphore &gt; 0 Less

Semaphores is used to share the resources (a Section of code/task/Process/Thread with another) to use the code segments in a cooperative way. It is not necessary that the system is using a disciplined scheduler to schedule tasks/processes, it may be a global variable which can be polled &amp; wait for status/count by a section of code, until other section it using a particular section of code &amp; doesn't change its status/affect count after he is done. In OS related terminology such variables are named as Semaphores. For Example: Suppose we have a IR emitter in our system, if any task or multiple sources are allowed to send decoded data to IR ports/it may be done by some other controller on board which may be communicating through SPI/I2C bus. Problem 1: we are sending IR Signals, if they are mixed with other data/signal them whole packet will be of no meaning, they are generally commands to control an IR device (which understands exact pattern), will not understand that pattern. So, if two events from different task tries to send data or IR controller will destroy the data (IR command). Problem 2: If on board controller taking processed IR commands on SPI bus, then, only one device can be communicated over it through MOSI, as at a time CS can have only one value to select multiple devices on SPI bus at a time. So, a cheap solution without increasing hardware to send multiple commands, we can make some arrangement to queue up the events &amp; data in some buffer (it is up to implementation/as per requirement, what wold be processing sequence of commands to execute, either LIFO or FIFO can be used) &amp; send it to IR controller one by one. And that arrangement may be a semaphore. in which all tasks who want to send IR signal on some events (like some buttons for IR commands sending function associated are pressed by user on iPad &amp; is came through TCP, which invoked the tasks), we can not restrict user to not send multiple commands in short time or wait for first command to respond, but, i can have the semaphore lock, which will lock a critical section (IR sending over SPI bus in his case) &amp; won't release the lock until it is not sent successfully &amp; other queued up events &amp; data will wait for this lock to get released. Here one section (a task who received event) is locking the resource &amp; other is releasing it. Their is one more similar thing called Mutex, which is similar to semaphore, but, the difference is it can not be shared between different processes, semaphore can be shared between processes apart from local threads of a process. Mutex can only be unlocked by the task/process/thread who locked it. But if you forget to unlock them on correct places, they may make your code unresponsive, as in such cases resource remains locked for ever. Less

### 1b) Generate binary numbers till given N.

2 Answers

public static void main(String[] args) { // TODO Auto-generated method stub int n=100; String[] a= new String[n]; a[0]="0"; a[1]="1"; for(int i=2;i Less

Gave a brute force solution, O(N^2).

### 2a) Given an array of numbers , make another array such that element at new array is product of all the other elements except that element in older array,and 3ants puzzle and balance brackets question and open ended question.

2 Answers

I said in O(n) and he wanted to solve in DP, which i don't know.

Array Question: Find the product of all elements(prod) in the array. In a for loop, new_array[i]=prod/original_array[i]; Balance brackets to be solved using stack: Push when you encounter an open bracket and pop when you encounter close bracket. 3 ants puzzle: 2 directions for each ant and 3 ants are there. Therefore 2^3=8 combinations. Only when all ants move along same direction(either forward or backward) they DON'T collide. Therefore probability is 6/8. Less

### What are classes and objects

2 Answers

just gave the simple definitionand example

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### 1a) Given a string of characters , numbers and symbols reverse only the characters in the array.

2 Answers

Solved using two pointer method.

package com.rajabishek; public interface Stack { public void push(T item); public T peek(T item); public T pop(); public boolean isEmpty(); } package com.rajabishek; public class ArrayStack implements Stack{ private T[] data; private int top = -1; ArrayStack() { data = (T[])new Object[50]; } ArrayStack(int size){ data = (T[])new Object[size]; } public void push(T item) { if(top == data.length - 1) { System.out.println("Stack overflow"); return; } data[++top] = item; } public T peek(T item) { if(top == -1) { return null; } return data[top]; } public T pop() { if(top == -1) { System.out.println("Stack underflow"); return null; } return data[top--]; } public boolean isEmpty() { return top == -1; } } package com.rajabishek; public class Main { //Dependency Inversion - Don't hardcode the actual implementation public static void reverseLetters(char[] data, Stack stack) { for(char character : data) { if(Character.isLetter(character)) { stack.push(character); } } for(int i=0; i Less

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