# Tutorials (Java, Python, PHP, Bigdata, Algorithms & Data Structure), Interview Questions & Online Test

## What is HeapSort Algorithm Example and Implementation

Heap sort is a Heap data structure based comparison sorting technique where we first find the maximum element and place the maximum element at the end. We repeat the same process for remaining elements.

## How Cassandra Read Works (Partitioner, Snitches)

How Cassandra Read Works what are Partitioner and Snitches in Cassandra, Optimizing Reads in Cassandra using Bloom filters, Row Cache, Key Cache and Linux page caching.

## How Cassandra Write Works (Commit Log, Memtable, SSTable)

When a write request comes to any node in a Cassandra cluster, the node is called Coordinator for the request and acts as a proxy between the client and the replicas throughout the request cycle.

## Apache Kafka Architecture and Design

Kafka is distributed, that means it run as a cluster on multiple nodes called brokers, even brokers can span on multiple datacenters. A distributed system is Horizontally scalable and fault-tolerance.

## Activity Selection Problem

In and Activity Selection Problem we are given a set of activities with their start and finish time, the task is to find out the maximum number of activities completed by a single person.

## Find subarrays with given sum in an array

Given an array A with length N, the task is to print all possible subarrays whose sum is equals to a given number "sum".

## Find index that divides an array into two subarrays of equal sum

Find index that divides an array into two subarrays of equal sum, The task is to find the index that divides the array into two subarrays of equal sum. If the array can not be divided in equal sum the method should return -1

## Check for duplicate elements within a given range k in an array

Given an array A with length n, the task is to find duplicates within a given range k in the array. We can solve this problem in O(n) time using O(n) extra space.

## Merge two sorted arrays in O(n+m) time and O(m+n) extra space

Given two sorted arrays, A1, A2 the task is to merge them in a sorted manner. We can solve this problem in O(n1+n2) time and O(n1+n2) extra space.

## Segregate positive and negative numbers in Array

Given an array arr[] with length n, the task is to rearrange the array is such a way so that the output array should contain all the negative elements in the starting of the array followed by all positive integers.