eComStreet Interview Questions and Answers

My day was productive and fulfilling. As for myself, I am a driven and detail-oriented individual with a passion for problem-solving.

• I tackled several challenging tasks at work and made significant progress on each of them.

• I also took some time to exercise and clear my mind, which helped me stay focused throughout the day.

• As for myself, I have a background in engineering and enjoy using my analytical skills to find cre...read more

Optimizing code involves identifying and removing bottlenecks to improve performance.

• Identify the parts of the code that are taking the most time to execute

• Use efficient algorithms and data structures

• Minimize the number of function calls and loops

• Avoid unnecessary calculations or operations

• Use caching or memoization to avoid repeating calculations

• Profile the code to measure performance improvements

Optimized version of given code

• Use efficient data structures and algorithms

• Avoid unnecessary loops and conditions

• Minimize function calls and variable assignments

My day was productive and fulfilling. As for myself, I am a driven and detail-oriented individual with a passion for problem-solving.

• I tackled several challenging tasks at work and made significant progress on each of them.

• I also took some time to exercise and clear my mind, which helped me stay focused throughout the day.

• As for myself, I have a background in engineering and enjoy applying my analytical skills to a var...read more

Yes, I prefer coding in C and have read The C Programming Language book. I have also explored the concept of Inheritance in C.

• I find C to be a powerful and efficient language for system programming.

• Yes, I have read The C Programming Language book by Dennis Retchie and found it to be a great resource.

• Recently, I have been exploring the concept of Inheritance in C through various online resources and tutorials.

• While C do...read more

Inheritance allows a class to inherit properties and methods from another class.

• Inheritance promotes code reusability and saves time and effort in programming.

• It allows for the creation of a hierarchy of classes with shared characteristics.

• For example, a class Animal can be inherited by classes such as Dog, Cat, and Bird, which share common properties and methods.

• Inheritance can be implemented using the 'extends' keywo

Liskov substitution principle is a principle in object-oriented programming that states that objects of a superclass should be able to be replaced with objects of its subclasses without affecting the correctness of the program.

• Subtypes must be substitutable for their base types

• Derived classes must not change the behavior of the base class

• Violating the principle can lead to unexpected behavior and errors

• Example: A squar...read more

Explanation of OOPs concepts with programs

• Encapsulation: Wrapping data and functions into a single unit. Example: Class in Java

• Abstraction: Hiding implementation details and showing only necessary information. Example: Abstract class in C#

• Inheritance: Acquiring properties and behavior of a parent class. Example: Child class extending parent class in Python

• Polymorphism: Ability of an object to take many forms. Example:

Dynamic polymorphism is achieved through virtual functions and inheritance in object-oriented programming.

• Create a base class with virtual functions

• Create derived classes that override the virtual functions

• Use pointers or references of the base class to call the virtual functions

• The appropriate derived class function will be called based on the object being pointed to or referred to

Global variables can lead to unexpected changes and make debugging difficult.

• Global variables can be accessed and modified from any part of the code, making it difficult to track changes.

• They can cause naming conflicts if multiple variables with the same name are used in different parts of the code.

• Using global variables can make it harder to test and debug code, as it can be difficult to isolate the cause of errors.

• Th...read more

Using 'goto' can make code hard to read, maintain and debug.

• Goto statements can create spaghetti code that is difficult to follow.

• It can make it harder to understand the flow of the program.

• It can also make debugging more difficult.

• There are usually better alternatives to using goto, such as using loops or functions.

• Some programming languages, such as Java and Python, do not even have a goto statement.

• Using goto can al...read more

My favorite subject is history because it helps me understand the present and learn from the past.

• I enjoy learning about different cultures and how they have evolved over time

• I find it fascinating to study the causes and effects of major historical events

• One of my favorite books on history is 'Guns, Germs, and Steel' by Jared Diamond

Implicit objects are pre-defined objects in JSP that can be accessed without being explicitly declared.

• Implicit objects are created by the JSP container during the translation phase.

• They can be accessed using predefined names such as request, response, session, application, out, pageContext, config, and exception.

• For example, the request object can be used to retrieve parameters from a form or URL.

• The session object ca...read more

Apache is a popular web server and Tomcat is a widely used application server.

• Apache is an open-source web server that supports multiple operating systems and is known for its stability and security.

• Tomcat is a Java-based application server that is used to deploy Java web applications and supports servlets and JSPs.

• Other popular web servers include Nginx and Microsoft IIS.

• Other popular application servers include JBoss...read more

To deploy a web application on Apache Tomcat, the application needs to be packaged as a WAR file and then deployed to the Tomcat server.

• Create a WAR file of the web application

• Copy the WAR file to the Tomcat webapps directory

• Start the Tomcat server

• Access the web application using the URL http://localhost:8080/

• Collections in Java are classes that implement collections of objects, such as lists, sets, and

A program to swap two pointers.

• Declare two pointers of the same data type

• Assign the first pointer to a temporary variable

• Assign the second pointer to the first pointer

• Assign the temporary variable to the second pointer

Dijkstra's algorithm finds shortest path between nodes in a graph

• Create a graph with nodes and edges

• Initialize distances from source node to all other nodes as infinity

• Set distance from source node to itself as 0

• Create a set of unvisited nodes

• While unvisited set is not empty, select node with minimum distance

• For each neighbor of selected node, calculate distance from source node

• If calculated distance is less than curre...read more

Floyd-Warshall's algorithm is used to find the shortest path between all pairs of vertices in a weighted graph.

• Create a 2D array to store the distances between all pairs of vertices.

• Initialize the array with the weights of the edges in the graph.

• Use nested loops to iterate over all pairs of vertices and update the distances if a shorter path is found through a third vertex.

• The final array will contain the shortest dist

Program to print matrix elements in spiral order recursively

• Create a recursive function to print the elements in spiral order

• Define the boundaries of the matrix and traverse the matrix in spiral order

• Call the recursive function to print the elements in spiral order

• Handle edge cases such as empty matrix or matrix with only one row/column

Find two numbers in an unsorted array that add up to a given sum in O(n)

• Use a hash table to store the difference between the sum and each element in the array

• Iterate through the array and check if the current element is in the hash table

• If it is, return the current element and the corresponding difference

• If not, add the current element to the hash table

Indexing is a technique used in DBMS to improve the performance of queries.

• Indexing creates a separate data structure that allows faster retrieval of data.

• It works by creating a pointer to the location of data in the table.

• Indexes can be created on one or more columns of a table.

• Types of indexing include B-tree, hash, and bitmap indexing.

• Indexes can also be clustered or non-clustered.

• Clustered indexes determine the phy...read more

B and B+ trees are data structures used for efficient searching and sorting of large datasets.

• B trees are balanced trees used for disk-based storage systems.

• B+ trees are similar to B trees but have all data stored in the leaf nodes for faster searching.

• B trees have a variable number of keys per node, while B+ trees have a fixed number.

• B trees have a higher fanout than B+ trees, making them more efficient for smaller da...read more

Program to find lowest common ancestor of two nodes in binary search tree and binary tree with brute force approach.

• For binary search tree, traverse from root to both nodes and store the path. Then compare paths to find LCA.

• For binary tree, traverse from root to both nodes and store the path. Then compare paths to find LCA.

• Brute force approach involves checking each node's descendants to see if they contain both nodes.

• ...read more

Program to print all ancestors of a node in a binary tree

• Create a recursive function to traverse the binary tree

• Check if the current node is the target node

• If yes, print all the nodes in the call stack

• If not, recursively call the function for left and right subtrees

Merge Sort is a divide and conquer algorithm that sorts an array by dividing it into two halves, sorting them separately, and then merging the sorted halves.

• Divide the array into two halves

• Recursively sort the two halves

• Merge the sorted halves

Find pairs of integers in a BST whose sum is equal to a given number.

• Traverse the BST and store the values in a hash set.

• For each node, check if (X - node.value) exists in the hash set.

• If yes, add the pair (node.value, X - node.value) to the result.

• Continue traversal until all nodes are processed.

Merge overlapping time intervals into mutually exclusive intervals.

• Sort the intervals based on their start time.

• Iterate through the intervals and merge overlapping intervals.

• Output the mutually exclusive intervals.

• Example: [(1,3), (2,6), (8,10), (15,18)] -> [(1,6), (8,10), (15,18)]

Different types of hashing and alternative for Linear Chaining

• Different types of hashing include division, multiplication, and universal hashing

• Alternative for Linear Chaining is Open Addressing

• Open Addressing includes Linear Probing, Quadratic Probing, and Double Hashing

An AVL tree is a self-balancing binary search tree where the heights of the left and right subtrees differ by at most one.

• AVL tree is a binary search tree with additional balance factor for each node.

• The balance factor is the difference between the heights of the left and right subtrees.

• Insertion and deletion operations in AVL tree maintain the balance factor to ensure the tree remains balanced.

• Rotations are performed ...read more

Find the minimum number of squares whose sum equals to a given number n.

• Use dynamic programming to solve the problem efficiently.

• Start with finding the square root of n and check if it is a perfect square.

• If not, then try to find the minimum number of squares required for the remaining number.

• Repeat the process until the remaining number becomes 0.

• Return the minimum number of squares required for the given number n.

Insertion sort for a singly linked list.

• Traverse the list and compare each node with the previous nodes

• If the current node is smaller, swap it with the previous node

• Repeat until the end of the list is reached

• Time complexity is O(n^2)

Implemented a new customer feedback system that increased customer satisfaction by 20%

• Implemented a new customer feedback system to gather insights and improve customer experience

• Analyzed feedback data to identify common issues and areas for improvement

• Implemented changes based on feedback to address customer concerns and enhance overall satisfaction

• Trained team members on how to effectively use the new system and inte...read more